Proportions (unit rate)
When two quantities grow together at the same rate, find the value of one unit and multiply. It works for price per kilo, hourly rates and consumption.
About: Proportions (unit rate)
When two quantities grow together at the same rate, find the value of one unit and multiply. It works for price per kilo, hourly rates and consumption.
Worked examples
If 5 kg of coffee cost $45, how much do 6 kg cost?
Answer: 54. Find the value of one unit: 45 ÷ 5 = 9. Then multiply: 9 × 6 = 54.
A contractor charges $54 for 6 hours. How much for 7 hours at the same rate?
Answer: 63. Find the value of one unit: 54 ÷ 6 = 9. Then multiply: 9 × 7 = 63.
A contractor charges $99 for 3 hours. How much for 7 hours at the same rate?
Answer: 231. Find the value of one unit: 99 ÷ 3 = 33. Then multiply: 33 × 7 = 231.