<PRE><B>Question 519251</B>
Let
Present age of Man = m
Present age of Son = s


A man is 3 times as old as his son. 
m=3s.......(1)
8 years ago,
Man age = m-8
Song age = s-8
Then, the product of their age was 112.
(m-8)(s-8)=112
ms-m8-8s+64=112
ms-m8-8s=112-64
ms-m8-8s=48..............(2)
Substitute the value from (1) to (2)
(3s)s-(3s)8-8s=48
3s^2-24s-8s=48
3s^2-32s=48
3s^2-32s-48=0
3s^2-36s+4s-48=0
3s(s-12)+4(s-12)=0
(s-12)(3s+4)=0
s-12=0 or 3s+4=0
s=12 or s=-4/3 (inadmissable)
so
s=12
Put the value of s in (1)
m=3s
m=3(12)
m=36

Present age of Man = m = 36 years old
Present age of Son = s = 12 years old
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