Question: If the ratio of boys to girls in a class is 4:5 and there are 36 boys, how many girls are there?

Options:

1. 45
2. 40
3. 50
4. 30

Correct Answer: 45

Solution:

Let the number of girls be x. The ratio gives us 36/x = 4/5. Cross-multiplying gives 4x = 180, so x = 45.