Question

A bag contains 90 balls.

The ratio of red to blue to yellow balls is 2:7:1
Find how many red, blue and yellow balls there are.

Answer 1

18 red, 63 blue and 9 yellow

Explanation:

→ Add the ratios together

90 ÷ ( 2 + 7 + 1 ) = 9

→ Multiply each ratio by

2 × 9 = 18 red

7 × 9 = 63 blue

1 × 9 = 9 yellow

Answer 2

r+b+y=90
k=90:3=30
r=2*k=60
b=7*k=210
y=1*k=30