17
Solutions with relevant marking scheme to Board Question papers available in downloadable PDF format at www.targetpublications.org/tp10186 Printed at: India Printing Works, Mumbai P.O. No. 35934 10186_11090_JUP © Target Publications Pvt. Ltd. No part of this book may be reproduced or transmitted in any form or by any means, C.D. ROM/Audio Video Cassettes or electronic, mechanical including photocopying; recording or by any information storage and retrieval system without permission in writing from the Publisher. Salient Features Comprises a total of 27 Test Papers: (15 Model Question Papers + 12 Board Question Papers) Provides 3 Model Question Papers with solutions and 2 Additional Practice Question Papers without solutions for each subject for better preparation. Consists Board Question Papers of 2015 and 2016. 15 Model Question Papers 12 Board Question Papers

15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

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Page 1: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

Solutions with relevant marking scheme to Board Question papers available

in downloadable PDF format at www.targetpublications.org/tp10186

Printed at: India Printing Works, Mumbai

P.O. No. 35934

10186_11090_JUP

© Target Publications Pvt. Ltd. No part of this book may be reproduced or transmitted in any form or by any means, C.D. ROM/Audio Video Cassettes or electronic, mechanical

including photocopying; recording or by any information storage and retrieval system without permission in writing from the Publisher.

Salient Features

• Comprises a total of 27 Test Papers:

(15 Model Question Papers + 12 Board Question Papers)

• Provides 3 Model Question Papers with solutions and 2 Additional Practice

Question Papers without solutions for each subject for better preparation.

• Consists Board Question Papers of 2015 and 2016.

15 Model Question Papers12 Board Question Papers

Page 2: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

 

Preface

“SSC Question Paper Set” is a penultimate weapon, designed to facilitate thorough preparation for

the students appearing for the SSC Board Examination. The book includes 15 Model Questions Papers across three subjects – 3 Solved Question Papers and 2

Practice Question Papers for each subject. These Question Papers are in tune with the changed syllabus and

are prepared based on the latest paper pattern. Additionally, 12 Board Question Papers (2015 and 2016) have

been included to gear up the students for the Examination. The Model Answer Papers offer complete answers

for every question with the relevant marking scheme to make sure the students encounter no scope for error. Solutions to Board Question Papers of 2015 and 2016 examinations are available in downloadable

PDF format at our website www.targetpublications.org. The purpose behind this is to make students familiar

with the current question paper pattern and marking schemes. It also gives them a holistic understanding of

the exact nature of the board question papers.

As the old adage goes, “Practice makes a man Perfect”, students will find here, a goldmine of

Question Papers to practice, before they are up for their final battle. We are sure these Question Papers will

prove to be extremely instrumental in achieving monumental scores in the Board Examinations.

The journey to create a complete book is strewn with triumphs, failures and near misses. If you think

we’ve nearly missed something or want to applaud us for our triumphs, we’d love to hear from you.

A book affects eternity; one can never tell where its influence stops.

We wish the students all the best for their examinations.

Yours faithfully,

Publisher.

Page 3: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

Index

Subject Page No.

Marking Scheme Algebra/Geometry 1

Science 3

No. Subject Test Page No.

Question Papers Model Answers

1. Algebra

1 5 78 2 7 86 3 9 93 4 11

For Additional Practice 5 13

2. Geometry

1 15 101 2 17 110 3 20 119 4 22

For Additional Practice 5 24

3. Science &

Technology

1 (Section A) 26 129 1 (Section B) 28 133 2 (Section A) 30 137 2 (Section B) 32 141 3 (Section A) 34 144 3 (Section B) 36 148 4 (Section A) 38

For Additional Practice 4 (Section B) 40 5 (Section A) 42 5 (Section B) 44

No. Board Question

Paper Subject

Page No.

Question Papers Model Answers

1. March 2015

Algebra 46

Solutions in downloadable

PDF format available at

www.targetpublications.org

Geometry 48

Science & Technology 50

2. July 2015 Algebra 53

Geometry 55 Science & Technology 57

3. March 2016 Algebra 61

Geometry 63 Science & Technology 65

4. July 2016 Algebra 69

Geometry 71 Science & Technology 73

Page 4: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

1

 

   

Algebra/Geometry

ALGEBRA / GEOMETRY : MARKING SCHEME 

Marking Scheme (for March 2014 exam and onwards)

Written Exam

Algebra 40 Marks Time: 2 hrs.

Geometry 40 Marks Time: 2 hrs.

* Internal Assessment 20 Marks

Total 100 Marks

* Internal Assessment

Home Assignment: 10 Marks 5-5 Home assignment for Algebra and Geometry

of 10 marks each would be given. Marks

obtained out of 100 would be converted to marks

out of 10.

10 Marks Depending upon the entire syllabus, internal test

for Algebra and Geometry with 20 marks each

would be taken at the end of second semester.

Marks obtained out of 40 would be converted to

marks out of 10.

Total 20 marks

ALGEBRA AND GEOMETRY

Mark Wise Distribution of Questions

Marks Marks with Option 6 sub questions of 1 mark each: Attempt any 5 05 06

6 sub questions of 2 marks each: Attempt any 4 08 12

5 sub questions of 3 marks each: Attempt any 3 09 15

3 sub questions of 4 marks each: Attempt any 2 08 12

3 sub questions of 5 marks each: Attempt any 2 10 15

Total: 40 60

Weightage to Types of Questions

Sr. No.

Type of Questions Marks Percentage of Marks

1. Very short answer 06 10

2. Short answer 27 45

3. Long answer 27 45

Total: 60 100

Test of multiple choicequestion:

Page 5: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

   

   

Marking Scheme

2

Weightage to Objectives

Sr. No

Objectives Algebra

Percentage marks Geometry

Percentage marks 1. Knowledge 15 15 2. Understanding 15 15 3. Application 60 50 4. Skill 10 20 Total: 100 100

Unit wise Distribution: Algebra

Sr. No.

Unit Marks with option

1. Arithmetic Progression 12 2. Quadratic equations 12 3. Linear equation in two variables 12 4. Probability 10 5. Statistics – I 06 6. Statistics – II 08

Total: 60

Unit wise Distribution: Geometry

Sr. No.

Unit Marks with option

1. Similarity 12 2. Circle 10 3. Geometric Constructions 10 4. Trigonometry 10 5. Co-ordinate Geometry 08 6. Mensuration 10

Total: 60

Page 6: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

3

 

   

Science and Technology

SCIENCE & TECHNOLOGY : MARKING SCHEME 

Marking Scheme (for March 2014 exam and onwards)

Total Marks: 100

Written examination: 80 Marks

Two separate question paper has to be solved on separate answer sheets.

Paper I: 40 Marks: 2 hours

Paper II: 40 Marks: 2 hours

Practical examination: 20 Marks: 1 hour 30 minutes

Question Paper pattern:

Questions Marks Marks with option

Paper - I (Section A)

Q. 1 A. Answer 5 questions. (1 mark question) 5 5

Q. 1 B. Answer 5 MCQs. (1 mark question) 5 5

Q. 2. Answer any 5 out of 6. (2 marks question) 10 12

Q. 3. Answer any 5 out of 6. (3 marks question) 15 18

Q. 4. Answer any 1 out of 2. (5 marks question) 5 10

Paper - II (Section B)

Q. 1 A. Answer 5 questions. (1 mark question) 5 5

Q. 1 B. Answer 5 MCQs. (1 mark question) 5 5

Q. 2. Answer any 5 out of 6. (2 marks question) 10 12

Q. 3. Answer any 5 out of 6. (3 marks question) 15 18

Q. 4. Answer any 1 out of 2. (5 marks question) 5 10

Total 80 100

Page 7: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

   

   

Marking Scheme

4

Types of Questions for Paper I and Paper II

Q. 1 A Fill in the blanks, Find odd man out, Find co-relation, Match the pairs, State true or false, Name, Write unit or molecular formula Q. 1 B Multiple choice questions based on practicals.

Q. 2

Give reasons, Draw / correct diagrams, Write note, Write balanced chemical equation, Laws, Definitions, Solve examples, Distinguish, Complete the table, Write characteristics, Write uses. Q. 3

Give two examples and explain any one, Write law / definition and explain with example, Write merits-demerits, Explain. Q. 4

Prove, Explain working with appropriate diagram, Long question, Explain with given points – principle, diagram, construction, working, use, Questions based on given paragraph About HOTS questions

HOTS questions means Higher Order Thinking Skill questions. Approx. 20% questions are HOTS questions and are based on the syllabus. HOTS questions can be of 1 mark to 5 marks. In depth study of textbook helps in answering HOTS questions. Chapter wise weightage:

No. Chapter Name Marks Marks with option

1 School of elements 4 5

2 The magic of chemical reactions 4 6

3 The acid base chemistry 4 5

4 The electric spark 5 7

5 All about electromagnetism 6 7

6 Wonders of light (Part I) 7 8

7 Wonders of light (Part II) 6 7

8 Understanding metals and non-metals 7 9

9 Amazing world of carbon compounds 5 7

10 Life’s internal secrets 6 7

11 The regulators of life 6 7

12 The life cycle 6 7

13 Mapping our genes 6 8

14 Striving for better environment (Part I) 4 5

15 Striving for better environment (Part II) 4 5

Page 8: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

5

Algebra

S.S.C. Preliminary Examination  1 ALGEBRA 

Time: 2 Hours Total Marks: 40 Note: i. All questions are compulsory. ii. Use of calculator is not allowed. Q.1. Attempt any five of the following sub-questions: [5]

i. If 12x + 13y = 29 and 13x + 12y = 21, then find x y.

ii. Write Dy for the following simultaneous equation: 5x 2y = 10 ; 3x y = 11

iii. Determine whether the given value of x is a root of given quadratic equation: 4x2 9 = 0,     

x = 3

2

iv. From the total expenditure, expenditure on education is 20%. Write the measure of the central angle to show in pie diagram.

v. Two coins are tossed. Write the sample space for the given experiment.

vi. Write the following quadratic equation in standard form: x 6

x = 5

Q.2. Attempt any four of the following sub-questions: [8] i. Find the value of the following determinant:

3 6 4 2

5 3 2

ii. Write the first four terms of the A. P. where a = 10, d = 3. iii.

Class Frequency

5 15 7

15 25 10

25 35 20

35 45 13 Find the mean of given data by ‘Direct Method’. iv. Find S10, if a = 6 and d = 3.

v. Form a quadratic equation whose roots are 3 and 5

2.

vi. A card is drawn from a pack of well shuffled 52 playing cards. Find the probability that the card drawn is a face card.

Q.3. Attempt any three of the following sub-questions: [9] i. Two digit numbers are formed from the digits 2, 3, 5, 7, 9 without repetition. Find the

probability of getting a. odd number b. two digit number so formed is multiple of 7

ii. Solve the following quadratic equation by formula method: 5m2 2m = 2.

iii. An obtuse angle of a rhombus is greater than twice the acute angle by 60. Find the measure of each angle.

iv. Find the three consecutive terms of an A.P. whose sum is 3 and the product of their cubes is 512.

Page 9: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

S.S.C. Question Paper

6

v. The following table gives information about the monetary investment by some residents in a city.

Mode of Investment Percentage of residents

Shares 10 Mutual funds 20 Real Estate 35

Gold 30 Govt. Bonds 5

Draw a pie diagram to represent the data. Q.4. Attempt any two of the following sub-questions: [8] i. If you spin the spinner, find the probability that it will point at a. odd number. b. multiples of 3. c. an even numbered white sector. d. number less than 4. ii. The following table gives the result of certain examination for 180 students. a. Find value of x. b. Draw histogram

Marks 0 – 10 10 – 20 20 – 30 30 – 40 40 – 50 50 – 60 No. of students 10 x 25 2x 55 30

iii. Below is the given frequency distribution of Daily wages (in `) of 130 workers.

Daily wages (in `) 80 84 85 89 90 94 95 99 100 104 105 109 No. of workers 10 20 25 40 30 5

Find the median daily wages of workers. Q.5. Attempt any two of the following sub-questions: [10] i. A publisher printed a certain number of copies of a book. If he had printed 2000 copies more,

each copy would have cost ` 5 less. If he had printed 1600 copies less, each copy would have cost him ` 10 more. Find the number of copies printed and the cost of each book.

ii. If one root of the quadratic equation ax2 + bx + c = 0 is the square of the other, show that b3 + a2c + ac2 = 3abc.

iii. A farmer borrows ` 1000 and agrees to repay with a total interest of ` 140 in 12 instalments, each instalment being less than the preceding instalment by ` 10. What should be his first and last instalment?

1

3 5

7

4

2

6

8

Page 10: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

S.S.C. Model Answer Paper

78

S.S.C. Preliminary Examination  1 

ALGEBRA Model Answer Paper 

Q. 1. Attempt any five of the following sub-questions:

i. Substituting equation 1st from equation 2nd ,

13x + 12y = 21

12x + 13y = 29

() () () x y = 8 x y = 8 [1]

ii. Dy = 5 10

3 11 [1]

iii. By putting x = 3

2 in L.H.S., we get

L.H.S. = 4x2 9

= 4 2

3

2

9

= 4 9

4 9

L.H.S. = 0 L.H.S. = R.H.S.

x = 3

2 is the root of the given quadratic equation. [1]

iv. Central angle for expenditure on education = 20

100 360 [½]

= 72 [½] v. When two coins are tossed, S = {HH, HT, TH, TT} [1]

vi. x 6

x = 5

Multiplying both sides by x, we get x2

6 = 5x x2 5x 6 = 0 [1] Q. 2. Attempt any four of the following sub-questions:

i. 3 6 4 2

5 3 2

= (3 6 2) (4 2 5 3 ) [1]

= 6 6 + 20 2 3 = 6 6 +20 6

= 6 (6 + 20) = 26 6

3 6 4 2

5 3 2

= 26 6 [1]

Page 11: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

79

Algebra

ii. Given, a = 10, d = –3

t1 = a = 10 [½]

t2 = t1 + d = 10 3 = 7 [½]

t3 = t2 + d = 7 3 = 4 [½]

t4 = t3 + d = 4 3 = 1 [½]

First four terms of A.P. are 10, 7, 4, 1. iii.

Class Class mark

(xi) Frequency

(fi) fi xi

5 15 10 7 70

15 25 20 10 200

25 35 30 20 600

35 45 40 13 520

Total: fi = 50 fi xi = 1390

Mean = x = i i

i

1390

50

f x

f= 27.8

Mean = 27.8 [1] iv. Given, a = 6 ,d = 3

Sn = n

2[2a + (n 1)d] [½]

S10 = 10

2 [2 6 + (10 1)3] [½]

= 5 (12 + 27)

= 5 (39)

S10 = 195 [1]

v. Let, = 3 and = 5

2

then, + = 3 + 5

2 =

1

2

[½]

and = 3 5

2 =

15

2

[½]

the required quadratic equation is

x2 ( + ) x + = 0 [½]

i.e., x2 1

2

x + 15

2

= 0

i.e., 2x2 + x 15 = 0 ….[Multiplying both sides by 2] [½] vi. From a pack of 52 cards, a card is drawn

n(S) = 52 [½]

Let A be the event that the card drawn is a face card.

n(A) = 12 [½]

P(A) = n(A) 12 3

n(S) 52 13

P(A) 3

=13

[1]

[1]

Page 12: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

S.S.C. Model Answer Paper

80

Q. 3. Attempt any three of the following sub-questions: i. S = {23, 25, 27, 29, 32, 35, 37, 39, 52, 53, 57, 59, 72, 73, 75, 79, 92, 93, 95, 97} n(S) = 20 [1] a. Let A be the event of getting odd number A = {23, 25, 27, 29, 35, 37, 39, 53, 57, 59, 73, 75, 79, 93, 95, 97} n(A) = 16

P(A) = n(A) 16

n(S) 20

P(A) = 4

5 [1]

b. Let B be the event that two digit number is a multiple of 7. B = {35} n(B) = 1

P(B) = n(B) 1

n(S) 20

P(B) = 1

20 [1]

ii. The given equation is 5m2 2m = 2 i.e., 5m2 2m 2 = 0 Comparing it with am2 + bm + c = 0, we get a = 5, b = 2, c = 2 [½]

m = 2b b 4ac

2a

[½]

= 2( 2) ( 2) 4 5 ( 2)

2 5

[½]

= 2 44

10

[½]

= 2 2 11

10

[½]

= 2 1 11

10

m = 1 ± 11

5 [½]

iii. Let ABCD be a rhombus.

Let m A = x and mB = y According to the given condition,

y = 2x + 60 2x y = 60 ….(i) [1] In rhombus, adjacent angles are supplementary

x + y = 180 ….(ii) [1] Adding equation (i) and (ii),

2x y = 60 x + y = 180 3x = 120 x = 40 Substituting x = 40 in equation (ii), we get

40 + y = 180 y = 140 The measures of angle A, B, C and D are 40, 140, 40 and 140 respectively. [1]

A

CD

B

x y

Page 13: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

81

Algebra

iv. Let the three consecutive terms of A.P. be a d, a, a + d

According to the first condition,

a d + a + a + d = 3

a = 1 ….(i) [½]

According to the second condition,

(a d)3 (a)3 (a + d)3 = 512 [½]

(a d) (a) (a + d) = 8 .…[Taking cube root on both sides]

a (a2 d2) = 8

–1 [(1)2 d2] = 8 ….[From (i)]

–1 (1 – d2) = 8

1 + d2 = 8

d2 = 9

d = 3 [1]

When d = 3 and a = –1, the required terms are 4, 1, 2 [½]

When d = 3 and a = –1, the required terms are 2, 1, 4 [½] v.

Mode of Investment Percentage of residents Measure of Central angle ()

Shares 10 10

100 360 = 36

Mutual funds 20 20

100 360 = 72

Real Estate 35 35

100 360 = 126

Gold 30 30

100 360 = 108

Govt. Bonds 5 5

100 360 = 18

Total: 100 360 The pie diagram representation is as follows: [1½]

[1½]

126

108 18

36

72

Gold

Real Estate

Mutual Funds

Shares

Govt.Bonds

Page 14: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

S.S.C. Model Answer Paper

82

Q. 4. Attempt any two of the following sub-questions:

i. Since, the pointer can point at any numbers from 1 to 8.

n(S) = 8

a. Let A be the event that the spinner points at odd number.

A = 1, 3, 5, 7

n(A) = 4

P(A) = n(A)

n(S) =

4 1

8 2

P(A) = 1

2 [1]

b. Let B be the event that the spinner points at multiples of 3.

B = 3, 6

n(B) = 2

P(B) = n(B)

n(S) =

2

8 =

1

4

P(B) = 1

4 [1]

c. Let C be the event that the spinner points at even numbered white sector.

C =

n(C) = 0

P(C) = 0 [1] d. Let D be the event that the spinner points at a number less than 4.

D = 1, 2, 3

n(D) = 3

P(D) = n(D)

n(S) =

3

8

P(D) = 3

8 [1]

ii. Total number of students = 180

10 + x + 25 + 2x + 55 + 30 = 180

3x + 120 = 180

3x = 60

x = 20 [1]

Marks No. of students

0 – 10 10

10 20 20

20 30 25

30 40 40

40 50 55

50 – 60 30

Page 15: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

83

Algebra

iii.

Original class Class boundaries Frequency Cum. frequency less than type

80 – 84 79.5 – 84.5 10 10

85 – 89 84.5 89.5 20 30

90 – 94 89.5 94.5 25 55 c.f.

95 – 99 L 94.5 – 99.5 40 f 95

100 104 99.5 104.5 30 125

105 109 104.5 – 109.5 5 130

Here, fi = N = 130

N 130

2 2 = 65 [½]

Cumulative frequency (less than type) which is just greater than (or equal) to 65 is 95.

Median class is 94.5 99.5 [½]

[1]

Y

30

10

20

60

X

Y 605040 30 20 10 0

5

15

25

55

Scale: On X-axis: 1 cm = 10 marks On Y-axis: 1 cm = 5 students

Marks

40

50

35

45

N

o.of

stud

ents

X

[3]

Page 16: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

S.S.C. Model Answer Paper

84

Now, L = 94.5, c.f. = 55, h = 5, f = 40 [½]

Median = L + N h

- c.2

f.f

[½]

= 94.5 + 565 55

40

= 94.5 + 10 5

40

= 94.5 + 1.25 = 95.75 Median daily wages of workers is ` 95.75. [1] Q. 5. Attempt any two of the following sub-questions:

i. Let the publisher printed x copies and cost of each copy be ` y.

amount invested by publisher = ` xy [1]

According to first condition,

(x + 2000) (y 5) = xy

xy 5x + 2000y 10000 = xy

5x + 2000y = 10000 ….(i) [1]

According to second condition,

(x 1600) (y + 10) = xy

xy + 10x 1600y 16000 = xy

10x 1600y = 16000 ….(ii) [1]

Multiplying equation (i) by 2 and then adding with equation (ii), we get

10x + 4000y = 20000

10x 1600y = 16000 2400y = 36000 y = 15 [1] Substituting value of y in equation (ii), we get 10x 1600 15 = 16000 x = 4000 Number of copies printed are 4000 and cost of each book is ` 15. [1] ii. Let and be the two roots of the quadratic equation ax2 + bx + c = 0 According to the given conditon, = 2 [½]

Now, + = b

a

[½]

+ 2 = b

a

.… (i) [½]

Also, = c

a [½]

.2 = c

a

3 = c

a .… (ii) [½]

Now, cubing equation (i), we get

( + 2)3 =3

b

a

[½]

()3 + (2)3 + 3(2)( + 2) = 3

3

b

a

….[(a + b)3 = a3 + b3 + 3ab(a + b)] [½]

Page 17: 15 Model Question Papers 12 Board Question Papers · Marking Scheme Algebra/Geometry 1 Science 3 No. Subject Test Page No. Question Papers Model Answers 1. Algebra 1 5 78 2 7 86 3

85

Algebra

3 + (3)2 + 33( + 2) = 3

3

b

a

c

a+

2c

a

+ 3c

a

b

a

= 3

3

b

a

….[From (i) and (ii)] [½]

c

a +

2

2

c

a

2

3bc

a =

3

3

b

a

Multiplying both sides by a3,we get ca2 + c2a 3bc(a) = b3 b3 + a2c + ac2 = 3abc [1] iii. The instalment are in A.P. [½] Here, S12 = 1000 + 140 = 1140 [½] Also, n = 12, d = – 10 [½]

Now, Sn = n

2[2a + (n 1) d] [½]

S12 = 12

2 [2 a + (12 1) (10)] [½]

1140 = 6 [2a 110] 190 = 2a 110 a = 150 First instalment is ` 150 [1] Also, tn = a + (n 1) d [½] t12 = 150 + (12 1) ( 10) = 150 110 t12 = 40 Last instalment is ` 40 [1]