If the ratio of sugar to flour is 2 : 3 and sugar is 18, then flour is:

Correct answer: 27. 2 parts = 18, so 1 part = 9, and flour = 3 × 9 = 27.

Background: Find the value of one part first.

• 24: 24 is 3 × 8.
• 25: 25 is not a multiple of 3 parts.
• 30: 30 is 3 × 10.

Did you know? 1 part = given value ÷ its ratio number.

Memory trick: 18 ÷ 2 = 9, then × 3.