In a box of marbles, the ratio of red marbles to total marbles is 2:5. the ratio of green marbles to total marbles is 3:10. if the marbles that are neither red nor green are blue, how many blue marbles are in the box if there are 40 marbles in the box?
Accepted Solution
A:
Ratio:
Red : Total 2 : 5 (x2) (x2) 4 : 10
Green : Total 3 : 10
Total of red and green marbles = 4 + 3 = 7
Blue marbles = 10 - 7 = 3
10 parts = 40 marbles 1 part = 40 ÷ 10 = 4 3 parts = 4 x 3 = 12