Question

The sum of the ages of John and mary is 32. Four years ago, John was twice as old as mary . Find the present age of each

Answer 1

John is 20

Mary is 12

Explanation:

We can use one variable to define their ages because we know the relationship between their ages.

Mary is younger, let Mary's present age be x years,

Then John's present age is 32 − x years (Sum of their ages is (32)

4 years ago, they were both 4 years younger than now. Mary was ( x − 4 ) and John was ( 32 − x − 4 ) = ( 28 − x ) years old. John was twice as old as Mary:

2 ( x − 4 ) = 28 − x

2 x − 8 = 28 − x

3 x = 28 + 8

3 x = 36

x = 12

Mary's age is 12 and John's age is 20