Answer:
John is 20
Mary is 12
Step-by-step 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
