Real World Inverses

When building a house, the number of days required to build is inversely proportional to with the number of workers. One house was built in 85 days by 5 workers. How many days would it take to build a similar house with 25 workers?

• 17

• 20

• 30

• 425

When renting a limo for prom, the number of people varies inversely with the cost per person. Originally there were 6 people and the cost per person was $48. If the number of people changed to 12, what would be the new cost per person?

• $24

• $96

• $8

• $4

For a given set of rectangles, the length is inversely proportional to the width. In one of these rectangles, the length is 25 and the width is 3. For this set of rectangles, calculate the width of a rectangle whose length is 5.

• 15

• 35

• 75

• 375

In kickboxing, it is found that the force, f, needed to break a board, varies inversely with the length, l, of the board. Write and solve an equation to answer the following question: If it takes 15 lbs of pressure for DJ to break a board 4 feet long, how many pounds of pressure will it take Emily to break a board that is 10 feet long?

• 6

• 3

• 60

• 12

The amount of time it takes for an ice cube to melt varies inversely to the air temperature, in degrees. At 55 degrees Fahrenheit, the ice will melt in 35 min. How long will it take the ice to melt if the temperature is 125 degrees?

• 15.4 minutes

• 17.5 minutes

• 22.6 minutes

• 79.5 minutes

For a given set of rectangles, the length is inversely proportional to the width. In one of these rectangles, the length is 18 and the width is 12. For this set of rectangles, calculate the width of a rectangle whose length is 27.

• 8

• 3

• 40.5

• 18