Direct and Inverse Proportion Study Guide

At Sec 2 camp, there is sufficient food for 48 students to last 6 days. If 12 students are absent from the camp, how many more days can the food last?

• 2

• 4

• 6

• 8

The number of hours to paint a house varies inversely with the number of painters working. A 2400-square foot house can be painted in 27 hours by 6 painters. How many painters would need to work in order to paint the house in 18 hours?

• 8 painters

• 10 painters

• 9 painters

• 11 painters

Solve the proportion.

• k=5

• k=3.3333333

• k=60

• k=90

g is directly proportional to b Given g=20 when b=4. Find g when b=7

• 35

• 5

• 15

• 23

The amount of money earned on a job is directly proportional to the number of hours worked.  If $70.00 is earned in 5 hours, how much money is earned in 22 hours of work?

• $2

• $308

• $1.57

• $265

What type of variation does this scenario represent?
The length of time you charge your cell phone
and the battery power 

• direct variation

• inverse variation

• joint variation

• none of these

The width of a rectangle varies inversely with its length. if the width is 4 when the length is 18, find the width when the length is 8.

• 9

• 72

• 36

• 2

The number of kilograms of water in a person’s body varies directly as the person’s mass.  A person with a mass of 90 kg contains 60 kg of water.  How many kilograms of water are in a person whose mass is 75 kg?

• 50 kg water

• 72 kg water

• 94 kg water

• 150 kg water

2.The amount of money spent at the gas station varies directly with the number of gallons purchased. When 9.5 gallons of gas were purchased the cost was $36.52. How much would 12 gallons of gas cost?

• Direct Variation

• Inverse Variation

The number of pencils sold varies directly as the cost. If 5 pencils cost $0.45, find the cost of 7 pencils.

• Direct Variation

• Inverse Variation