The time, T (seconds), it takes for a pot of water to boil is proportional to the amount, A
(litres), of water
It takes 200 seconds to boil 2.4 litres of water.
Work out how much water (to 1 DP) is in the pot if it boils in 180 seconds.

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.