Practice Proportional Reasoning in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The ability to recognize and work with multiplicative relationships between quantities. If one quantity doubles, a proportional quantity also doubles โ€” the ratio stays constant.

If 3 pizzas feed 12 people, how many feed 20? Think multiplication, not addition.

Showing a random 20 of 50 problems.

Example 1

easy
A map scale is 1 cm : 5 km. How many km is 4 cm?

Example 2

hard
A car travels 180 miles using 12 gallons. At this rate, how far can it go on 20 gallons?

Example 3

medium
Solve: x+16=53\frac{x + 1}{6} = \frac{5}{3}.

Example 4

medium
If 4 oranges cost \$2.40, how much do 7 oranges cost?

Example 5

challenge
On a map, 3 cm represents 45 km. Two cities are 105 km apart in reality. How far apart on the map?

Example 6

medium
If 7 machines produce 350 widgets per day, how many widgets do 10 machines produce per day?

Example 7

medium
A drink mix uses 3 scoops for 4 cups of water. How many scoops for 10 cups?

Example 8

easy
A recipe ratio of sugar to flour is 1 : 3. If you use 2 cups of sugar, how much flour?

Example 9

medium
A car uses 8 liters of fuel per 100 km. How much fuel for a 250 km trip?

Example 10

medium
A car uses 5 gallons to travel 150 miles. How many gallons to travel 240 miles?

Example 11

hard
If a:b:c=2:3:5a : b : c = 2 : 3 : 5 and the total a+b+c=80a + b + c = 80, find each value.

Example 12

medium
Tip is proportional to bill at a flat 18% rate. If the bill is \$45, find the tip.

Example 13

medium
Three workers paint 60 ft of fence in a day. How much can 5 workers paint in a day (same pace)?

Example 14

easy
A recipe that serves 4 people uses 10 cups of flour. How many cups are needed to serve 10 people?

Example 15

challenge
A 1:50 scale model of a building is 0.4 m tall. How tall is the real building, in meters?

Example 16

easy
If a:b=3:4a : b = 3 : 4 and a=9a = 9, find bb.

Example 17

easy
If 3 pizzas feed 12 people, how many people do 6 pizzas feed?

Example 18

easy
If a photo is enlarged so width goes from 4 in to 12 in, by what factor did it scale?

Example 19

easy
If a recipe for 4 servings uses 2 cups of milk, how many cups for 6 servings?

Example 20

easy
If 6x=25\frac{6}{x} = \frac{2}{5}, find xx.