2.5.H: Homework

Exercise 1

A delivery truck leaves Milwaukee traveling at an average rate of 52 miles per hour. How far will it travel in 6 hours?

Answer

312 miles

Exercise 2

How long does it take the truck in Exercise 1 to travel 429 miles?

Answer

8.25 hours (8 hours and 15 minutes)

Exercise 3

A hiker begins walking along a trail at 9:00 a.m. at a rate of 3 mph. A friend starts from the same trailhead at 10:00 a.m. and walks at 5 mph.

Exercise 4

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 5

A machinist on lathe A can complete a job in 6 hours while the machinist on lathe B can complete it in 5 hours. If they work together, how long would it take them to complete the job?

Answer

2 hours and 44 minutes

Exercise 6

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 7

A nickel alloy that is 15% nickel is combined with an alloy that is 45% nickel. The final mixture is 800 kilograms that is 30% nickel.

How many kilograms of each alloy should be used?

Answer

400 kg of 15% alloy

400 kg of 45% alloy

Exercise 8

Vartan was paid $25,000 for a cell phone app that he wrote and wants to invest it to save for his son’s education. He wants to put some of the money into a bond that pays 4% annual interest and the rest into stocks that pay 9% annual interest. If he wants to earn 7.4% annual interest on the total amount, how much money should he invest in each account?

Answer

$8000 at 4%, $17,000 at 9%

Exercise 9

Stephanie inherited $40,000. She wants to put some of the money in a certificate of deposit that pays 2.1% interest per year and the rest in a mutual fund account that pays 6.5% per year. How much should she invest in each account if she wants to earn 5.4% interest per year on the total amount?

Answer

$10,000 in CD, $30,000 in mutual fund

Exercise 10

To prepare a cleaning solution in a laboratory, a 30% hydrochloric acid solution is needed. You currently have 80 milliliters of a 65% hydrochloric acid solution . How many milliliters of water should be added to dilute the solution to the required concentration? Round answer to the nearest hundredth.

Answer

93.33 mL of water

Exercise 11

A zinc alloy that is 50% zinc is combined with an alloy that is 90% zinc. The result is 1200 kilograms of a mixture that is 75% zinc.

How many kilograms of each alloy should be used?

Answer

450 kg of 50% alloy

750 kg of 90% alloy