Question

The present age of P is three times that of his son Q. Five years ago the age of Q was one fourth of the age of P. What will be the number obtained by adding the age of P and Q five years from now

Answer 1

P=3Q
P-3Q=0-----eq1
5years ago
1/4P=Q
so,
P=4Q
P-4Q=0--------eq2
multiplying eq1 by 4 & eq2 by 3
4(P-3Q)=4
4P-12Q=4----eq3
3(P-4Q)=3
3P-12Q=3-------eq4
subtracting eq 3&4
4P-12Q=4
-3P+12Q=-3
P=1
putting in eq 3
4*1-12Q=4
-12Q=0
Q=0
=(P+5)+(Q+5)
=(1+5)+(0+5)
=6+5
=11ans