Question

In the box of Stones ,the ratio of red marbles is 2:5. the ratio of green stones to the total stones is 3:10 .if the stones that are neither red nor green are blue ,how many blue are in the box.if there are 40 marbles in the box?.

Answer 1

The answer is 12:40 or 3:10

8(2:5)= 16:40
4(3:10)=12:40

Add them and get 28:40 and minus 40-28 and get 12:40

To double check multiply the ratios in smaller numbers but have the same total ratio. Hoped this works!!