Question

A) John is twice as old as Mary. Five years ago he was three times as old. What is Mary’s age now?

Answer 1

Mary is 10 years old

Explanation:

John age is twice Mary age

Let John's age = 2y

Mary's age = y

Five years ago

John's age = 2y - 5

Mary's age = y - 5

John age was three times Mary age

John's age = 3(y - 5)

Mary's age= y -5

Equate John's age Five years ago to John's age Three times

i.e. John's age Five years ago = John's age Three times Mary

2y - 5 = 3 (y - 5)

2y - 5 = 3y - 15

-5 + 15 = 3y - 2y

10 = y

y = 10

Hence, Mary's age now is 10 years

Answer 2

Explanation:

m = mary now j = john now

j = 2m <=== given

(j-5) = 3 ( m-5) <=== given sub in j = 2m

(2m-5) = 3(m-5)

10 = m Mary is 10 y/o ( John is 20 )