The mum is 21 years older than the child. In 6 years from now the mum will be 5 times as old as the child. 
Question : Where's the father? 
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Solution : The mum is 21 years older than the child. 
M = C + 21 
In 6 years from now the mum will be 5 times as old as the child. 
M + 6 = (C + 6) x 5 
Hence, C + 21 + 6 = (C + 6) x 5 
C + 27 = 5C + 30 
-3 = 4C 
C = -3/4 = -9 months 
The child is -3/4 years old, it'll be born in 9 months. 
"So right now, the father is on top of the MOTHER!!"

 
