Ages of father and son add up to 50. Six years back father's age was 6 more than thrice his son's age. What will be father's age 6 years hence?

Correct option is B

Let the age of father be F and that of son be S.
F+S= 50 (Given)
S = 50- F
(i)
Six years back father's age was 6 more than thrice his son's age.
According to problem:
(F-6)=3(S6) + 6
(ii)
Substituting the value of equation (i) in (ii), we get:
F-6=3(50-F-6) + 6
F-63(44 - F) + 6
F-6=132 - 3F + 6
F + 3F = 132 + 6 + 6
=> 4F = 144
=>
F= 144/4
=> F = 36
So, father's age 6 years hence = (36 + 6) = 42