DRDO Multi tasking staff Model paper 3

Given, ages of two persons differ by 20 years
Let the age of two persons be ‘a’ and ‘b’ where ‘a’ is the elder one and ‘b’ is the younger one
Thus, a - b = 20 ----(1)
Now, 5 years ago, the elder one was 5 times as old as the younger one
Thus, a - 5 = 5(b - 5)
⇒ a = 5b - 20 ----(2)
Subtracting (1) - (2)
4b = 40
⇒ b = 10
Thus, a = 30
Ages of the two persons = 30, 10