Direct and Inverse Proportion Word Problems

Front

What is Direct Proportion?

Back

Direct proportion is a relationship between two quantities where an increase in one quantity results in a proportional increase in the other. For example, if 5 workers can complete a task in 10 days, then 10 workers can complete the same task in 5 days.

Front

What is Inverse Proportion?

Back

Inverse proportion is a relationship between two quantities where an increase in one quantity results in a proportional decrease in the other. For example, if 4 workers can complete a task in 12 days, then 2 workers will take 24 days to complete the same task.

Front

How do you solve a direct proportion problem?

Back

To solve a direct proportion problem, set up a ratio comparing the two quantities and use cross-multiplication to find the unknown value.

Front

How do you solve an inverse proportion problem?

Back

To solve an inverse proportion problem, multiply the two quantities together to find a constant, then use that constant to find the unknown value.

Front

If 5 workers take 16 days to complete an order, how many days would it take 10 people?

Back

8 days.

Front

If 3 people can paint a fence in 6 days, how many days would it take 2 people?

Back

9 days.

Front

If 3 boxes contain 450 pins, how many pins will there be in 5 boxes?

Back

750 pins.

Front

If 5 calculators cost £65, how much will 3 calculators cost?

Back

£39.

Front

If 3 minibuses can carry 42 passengers, how many passengers can 2 minibuses carry?

Back

28 passengers.

Front

What is the formula for direct proportion?

Back

The formula for direct proportion is y = kx, where k is the constant of proportionality.