Question

Mary's age is twice the sum of John's age and 3. The sum of both ages is 21 years. Find the age of each one.

Answer 1

m = 2(j + 3)

m + j = 21

m = 21 - j

equating first and third equations:-

2(j + 3) = 21 - j

2j + j = 21 - 6

3j = 15

j = 5

so m = 21 - 5 = 16

So Johns age is 5 and Mary's age is 16 answer