The ratio of two numbers is 3:2 and their sum is 90. What is their difference?

Sure, let's solve this step by step:

1. We know that the ratio of the two numbers is 3:2. This means that the first number is 3 parts of the whole and the second number is 2 parts of the whole. So, the whole is divided into 3 + 2 = 5 parts.

2. We also know that the sum of the two numbers is 90. This is the whole which is divided into 5 parts. So, each part is equal to 90 ÷ 5 = 18.

3. Therefore, the first number (3 parts) is 18 × 3 = 54 and the second number (2 parts) is 18 × 2 = 36.

4. The difference between the two numbers is 54 - 36 = 18.