Question

The ratio of red, blue, and white stars on the bedroom ceiling is 2:3:5. How many blue stars are there if there are 30 stars on the ceiling?

Answer 1

R : B : W
2 : 3 : 5

1. Find the total of the ratio (2 + 3 + 5 = 10)
2. Work out what you do to 10 to get 30 (multiply by 3)
3. Multiply the blue ratio by three (3 x 3 = 9)

Check:

Do the same to the other colours:
2 x 3 = 6 and 5 x 3 = 15

Add together 6, 9 and 15 - the answer is 30 which is correct.