Answers to Homework (12-8)

Answers to Homework (12-8)1) a = 4

3) c = 1

5) m = 1/3

7) p = -13/2

9) x = -4

11) z = -3, z = 2

13) e = 1

Warm ups

2 11 3

5 10 5 10

x y y x

x y x y

2 5 4

3 3x x x

Work ProblemsObjective: To solve work problems involving rational expressions (combined time).

Standard 5.0

Use this formula:

121

together togethe

alonalone e

r

Word Problem Notes 13) Working alone, Danielle can sweep a porch in 13 minutes. Gariella can sweep the same porch in 15 minutes. Find how long it would take them if they worked together.

Word Problem Notes 14) It takes Kali 12 minutes to sweep a porch. James can sweep the same porch in 13 minutes. Find how long it would take them if they worked together.

Word Problem Notes 15) It takes Daniel 15 hours to pick forty bushels of apples. Shawna can pick the same amount in 11 hours. If they worked together, how long would it take them?

Word Problem Notes 16) It takes Ryan 14 minutes to inflate twenty balloons. Jessica can inflate the same twenty balloons in 13 minutes. Find how long it would take them to work together.

WATCH OUT!A bathtub fills in 15 minutes when the

drain is closed. When the drain is open and the faucet is off, the tub drains in 20 minutes. How long would it take to fill the tub if the drain is open and the faucet is on?

115 20

x x

LCD: 6060 60

604

3

4 3 60x x 60minx

TOO•Anne can complete a project in 6 hours.

It takes Will 9 hours to do the same job. How long will it take them if they work together?

•18/5 hours•3 3/5 hours•3.6 hours•3 hours 36 minutes

Homework•Worksheet:

▫Problem Solving: Work Problems

Warm ups

Solving Review

Math Lab Review– If it takes Joe 45 minutes to prepare 20

greeting cards and it takes Lisa 30 minutes to prepare 20 greeting cards, how long will it take if they work together?

Joe 1 job Lisa 1 job 45 min 30 min

x = time in minutes to work together

121

together togethe

alonalone e

r

Equation

145 30

x x LCD: 90 90 90

902

3

2 3 90x x 5 90x

18minx

121

together togethe

alonalone e

r

Math Lab 1•Working alone, Franky can sweep a porch

in 13 minutes. Brian can sweep the same porch in 15 minutes. Find how long it would take them if they worked together?

Math Lab 2•It takes Emma 12 minutes to eat Kyle’s

candy. Michelle can eat Kyle’s candy in 8 minutes. How long would it take them if they worked together?

Math Lab 3•Working alone, H can wash her car in 3

hours. Natalie can wash her car in 30 minutes. Find how long it would take them if they worked together.

Math Lab 4•Working alone, Ava can plant a tree in 6

hours. Maro can plant a tree in 5 hours. Find how long it would take them if they worked together.

Practice Test Time!

•Multiple choice•Show all of your work •Stay on task