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7.6E: Exercises

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Practice Makes Perfect

Solve Uniform Motion Applications

In the following exercises, solve uniform motion applications

Exercise 1

Mary takes a sightseeing tour on a helicopter that can fly 450 miles against a 35 mph headwind in the same amount of time it can travel 702 miles with a 35 mph tailwind. Find the speed of the helicopter.

Answer

160 mph

Exercise 2

A private jet can fly 1210 miles against a 25 mph headwind in the same amount of time it can fly 1694 miles with a 25 mph tailwind. Find the speed of the jet.

Exercise 3

A boat travels 140 miles downstream in the same time as it travels 92 miles upstream. The speed of the current is 6mph. What is the speed of the boat?

Answer

29 mph

Exercise 4

Darrin can skateboard 2 miles against a 4 mph wind in the same amount of time he skateboards 6 miles with a 4 mph wind. Find the speed Darrin skateboards with no wind.

Exercise 5

Jane spent 2 hours exploring a mountain with a dirt bike. When she rode the 40 miles uphill, she went 5 mph slower than when she reached the peak and rode for 12 miles along the summit. What was her rate along the summit?

Answer

30 mph

Exercise 6

Jill wanted to lose some weight so she planned a day of exercising. She spent a total of 2 hours riding her bike and jogging. She biked for 12 miles and jogged for 6 miles. Her rate for jogging was 10 mph less than biking rate. What was her rate when jogging?

Exercise 7

Bill wanted to try out different water craft. He went 62 miles downstream in a motor boat and 27 miles downstream on a jet ski. His speed on the jet ski was 10 mph faster than in the motor boat. Bill spent a total of 4 hours on the water. What was his rate of speed in the motor boat?

Answer

20 mph

Exercise 8

Nancy took a 3 hour drive. She went 50 miles before she got caught in a storm. Then she drove 68 miles at 9 mph less than she had driven when the weather was good. What was her speed driving in the storm?

Exercise 9

Chester rode his bike uphill 24 miles and then back downhill at 2 mph faster than his uphill. If it took him 2 hours longer to ride uphill than downhill, l, what was his uphill rate?

Answer

4 mph

Exercise 10

Matthew jogged to his friend’s house 12 miles away and then got a ride back home. It took him 2 hours longer to jog there than ride back. His jogging rate was 25 mph slower than the rate when he was riding. What was his jogging rate?

Exercise 11

Hudson travels 1080 miles in a jet and then 240 miles by car to get to a business meeting. The jet goes 300 mph faster than the rate of the car, and the car ride takes 1 hour longer than the jet. What is the speed of the car?

Answer

60 mph

Exercise 12

Nathan walked on an asphalt pathway for 12 miles. He walked the 12 miles back to his car on a gravel road through the forest. On the asphalt he walked 2 miles per hour faster than on the gravel. The walk on the gravel took one hour longer than the walk on the asphalt. How fast did he walk on the gravel?

Exercise 13

John can fly his airplane 2800 miles with a wind speed of 50 mph in the same time he can travel 2400 miles against the wind. If the speed of the wind is 50 mph, find the speed of his airplane.

Answer

650 mph

Exercise 14

Jim’s speedboat can travel 20 miles upstream against a 3 mph current in the same amount of time it travels 22 miles downstream with a 3 mph current speed. Find the speed of the Jim’s boat.

Exercise 15

Hazel needs to get to her granddaughter’s house by taking an airplane and a rental car. She travels 900 miles by plane and 250 miles by car. The plane travels 250 mph faster than the car. If she drives the rental car for 2 hours more than she rode the plane, find the speed of the car.

Answer

50 mph

Exercise 16

Stu trained for 3 hours yesterday. He ran 14 miles and then biked 40 miles. His biking speed is 6 mph faster than his running speed. What is his running speed?

Exercise 17

When driving the 9 hour trip home, Sharon drove 390 miles on the interstate and 150 miles on country roads. Her speed on the interstate was 15 more than on country roads. What was her speed on country roads?

Answer

50 mph

Exercise 18

Two sisters like to compete on their bike rides. Tamara can go 4 mph faster than her sister, Samantha. If it takes Samantha 1 hours longer than Tamara to go 80 miles, how fast can Samantha ride her bike?

Solve Work Applications

In the following exercises, solve work applications.

Exercise 19

Mike, an experienced bricklayer, can build a wall in 3 hours, while his son, who is learning, can do the job in 6 hours. How long does it take for them to build a wall together?

Answer

2 hours

Exercise 20

It takes Sam 4 hours to rake the front lawn while his brother, Dave, can rake the lawn in 2 hours. How long will it take them to rake the lawn working together?

Exercise 21

Mary can clean her apartment in 6 hours while her roommate can clean the apartment in 5 hours. If they work together, how long would it take them to clean the apartment?

Answer

2 hours and 44 minutes

Exercise 22

Brian can lay a slab of concrete in 6 hours, while Greg can do it in 4 hours. If Brian and Greg work together, how long will it take?

Exercise 23

Leeson can proofread a newspaper copy in 4 hours. If Ryan helps, they can do the job in 3 hours. How long would it take for Ryan to do his job alone?

Answer

12 hours

Exercise 24

Paul can clean a classroom floor in 3 hours. When his assistant helps him, the job takes 2 hours. How long would it take the assistant to do it alone?

Exercise 25

Josephine can correct her students’ test papers in 5 hours, but if her teacher’s assistant helps, it would take them 3 hours. How long would it take the assistant to do it alone?

Answer

7 hours and 30 minutes

Exercise 26

Washing his dad’s car alone, eight year old Levi takes 2.5 hours. If his dad helps him, then it takes 1 hour. How long does it take the Levi’s dad to wash the car by himself?​​​​​​​

Exercise 27

Jackson can remove the shingles off of a house in 7 hours, while Martin can remove the shingles in 5 hours. How long will it take them to remove the shingles if they work together?

Answer

2 hours and 55 minutes

Exercise 28

At the end of the day Dodie can clean her hair salon in 15 minutes. Ann, who works with her, can clean the salon in 30 minutes. How long would it take them to clean the shop if they work together?

Exercise 29

Ronald can shovel the driveway in 4 hours, but if his brother Donald helps it would take 2 hours. How long would it take Donald to shovel the driveway alone?

Answer

4 hours

Exercise 30

It takes Tina 3 hours to frost her holiday cookies, but if Candy helps her it takes 2 hours. How long would it take Candy to frost the holiday cookies by herself?​​​​​​​

Everyday Math

Exercise 31

Dana enjoys taking her dog for a walk, but sometimes her dog gets away and she has to run after him. Dana walked her dog for 7 miles but then had to run for 1 mile, spending a total time of 2.5 hours with her dog. Her running speed was 3 mph faster than her walking speed. Find her walking speed.

Answer

3 mph​​​​​​​

Exercise 32

Ken and Joe leave their apartment to go to a football game 45 miles away. Ken drives his car 30 mph faster Joe can ride his bike. If it takes Joe 2 hours longer than Ken to get to the game, what is Joe’s speed?​​​​​​​

Writing Exercises

Exercise 33

In Example, the solution h=−4 is crossed out. Explain why.

Exercise 34

Paula and Yuki are roommates. It takes Paula 3 hours to clean their apartment. It takes Yuki 4 hours to clean the apartment. The equation 13+14=1t can be used to find t, the number of hours it would take both of them, working together, to clean their apartment. Explain how this equation models the situation.​​​​​​​

Self Check

ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

This table has three rows and four columns. The first row is a header row and it labels each column. The first column is labeled "I can …", the second "Confidently", the third “With some help” and the last "No–I don’t get it". In the “I can…” column the next row reads “solve uniform motion applications.” The next row reads, “solve work applications”. The remaining columns are blank.

ⓑ On a scale of 1–10, how would you rate your mastery of this section in light of your responses on the checklist? How can you improve this?

 

Rational Equation Number Applications

In the following exercises, solve number applications

Exercise 35

The sum of the reciprocals of two consecutive odd integers is 1663. Find the two numbers.

Answer

−9, −7

Exercise 36

The sum of the reciprocals of two consecutive odd integers is 28195. Find the two numbers.

Exercise 37

The sum of the reciprocals of two consecutive even integers is 512. Find the two numbers.

Answer

4, 6

Exercise 38

The sum of the reciprocals of two consecutive even integers is 1160. Find the two numbers

Exercise 39

The sum of the reciprocals of two consecutive integers is 1990. Find the two numbers.

Answer

−10, −9

Exercise 40

The sum of the reciprocals of two consecutive integers is 1990. Find the two numbers.

Exercise 41

The sum of a number and its reciprocal is 52. Find the number(s).

Answer

2, 12

Exercise 42

The sum of a number and its reciprocal is 4120. Find the number(s).

Exercise 43

The sum of a number and twice its reciprocal is 92. Find the number(s).

Answer

12, 4

Exercise 44

The sum of a number and twice its reciprocal is 176. Find the number(s).

Exercise 45

The sum of the reciprocals of two numbers is 158, and the second number is 2 larger than the first. Find the two numbers.

Answer

{23, 83} and {85, 25}

Exercise 46

The sum of the reciprocals of two numbers is 1615, and the second number is 1 larger than the first. Find the two numbers.

Exercise 47

When the same number is added to both the numerator and denominator of the fraction 37, the result is 23. What is the number?

Answer

The number added is 5.

Exercise 48

When the same number is added to both the numerator and denominator of the fraction 58, the result is 34. What is the number?

Exercise 49

When the same number is added to both the numerator and denominator of the fraction 38, the result is 16. What is the number?

Answer

The number added is 2.

Exercise 50

When the same number is added to both the numerator and denominator of the fraction 79, the result is 23. What is the number?

Exercise 51

When the same number is subtracted to both the numerator and denominator of the fraction 110, the result is 23. What is the number?

Answer

The number subtracted is 17.

Exercise 52

When the same number is subtracted to both the numerator and denominator of the fraction 34, the result is 56. What is the number?

Exercise 53

When the same number is subtracted from both the numerator and denominator of the fraction 712, the result is 12. What is the number?

Answer

2

Exercise 54

When the same number is added to both the numerator and denominator of the fraction 1315, the result is 89. What is the number?

Exercise 55

One-third of a number added to the reciprocal of number yields 136. What is the number?

Answer

x=12,6

Exercise 56

Four-fifths of a number added to the reciprocal of number yields 8110. What is the number?

Exercise 57

One-half of a number added to twice the reciprocal of the number yields 2. What is the number?

Answer

2

Exercise 58

One-fourth of a number added to four times the reciprocal of the number yields 103. What is the number?


This page titled 7.6E: Exercises is shared under a CC BY license and was authored, remixed, and/or curated by OpenStax.

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