Question

D) Two years ago Rehan was three times as old as his son and two years hence, twice his age will be
equal to five times that of his son. Then the sum of their present age is​

Answer 1

Let the age of Rehan be = x
Let the age of his son be = y

2 years ago,
(x-2) = 3(y-2)
x-2 = 3y-6
x= 3y-4
x-3y = -4 .....(i)

Two Years Hence,
2(x+2) = 5(y+2)
2x+4 = 5y+10
2x-5y=6 .....(ii)

2(x-3y) = (-4)2 [Multiplying by two on both sides]
2x-6y = -8 ....(iii)

Subtracting iii from ii
2x -5y -2x +6y = 6-(-8)
y = 6+8
y=14

Substituting y=14 in i
x-3(14) = -4
x - 42 = -4
x= 38

Sum of Present Ages = x+y = 38+14 = 52