Question

Adam age is 5 times as old as Charles.
In 8 years’ time, the sum of their ages will be equal to twice Adam’s present age. Find their present age.

Answer 1

Let Charles age be x

Adam age will be 5x  

8 years later , add 8 to both expressions

Charles age = x+8

Adam age = 5x+8

add their ages and equate them to twice adam's present age 2*5x

x+8+5x+8 = 2*5x

6x+16=10x

4x=16

x=4

x = Charles' age

Adam's age  5x = 5(4) = 20