Question

We know the details about the mother and child but where's the father? A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.

Answer 1

The mum is 21 years older than the child, so...
M = C + 21In 6 years from now the mum will be 5 times as old as the child.
M + 6 = (C + 6) * 5(C + 21)+ 6 = (C + 6) * 5
C + 27 = 5C + 30
-3 = 4C
C = -3/4The child is -3/4 years old, i.e. it'll be born in 9 month's time.
So, the father is probably nearby.

Answer 2

The mum is 21 years older than the child, so...
M = C + 21

In 6 years from now the mum will be 5 times as old as the child.
M + 6 = (C + 6) * 5

(C + 21)+ 6 = (C + 6) * 5
C + 27 = 5C + 30
-3 = 4C
C = -3/4

The child is -3/4 years old, i.e. it'll be born in 9 month's time.
So, the father is probably nearby.