When 5 children from class A join class B, the number of children in both classes is the same. If 25 children from B, join A, then the number of children in A becomes double the number of children in B. The ratio of the number of children in A to B is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 19 : 17.
Let the number of children in classes A and B be 'a' and 'b'.
According to the question,
a - 5 = b + 5
a - b = 10.................(1)
(b - 25) × 2 = a + 25
2b - a = 75...............(2)
On adding eq 1 and 2 we get,
b = 85.
If b = 85 then a = 95.
Required ratio = 95 : 85 = 19 : 17.