There are two boxes A and B and each of them has two different colors of balls – red and blue. Total number of balls in A is 40% less than that of B. If the number of red balls in A is 42 which is equal to the number of blue balls in B and the ratio of the number of red to blue balls in B is 13:7, then find the number of blue balls in A?
A. 25
B. 20
C. 30
D. 35
E. None of these
Sol:
Total number of balls in B = 20/7 * 42 = 120
Total number of balls in A = 120 * 60/100 = 72
Number of blue balls in A = 72 – 42 = 30
