Question

a man is 4times as old as his son.after 16 years he will be only twice as old as his son find their presents ages

Answer 1

let age of father be x years
and age of son be y years
father is 4 times as old as son
x=4y (1)
after 16 years he will be twice as his son
x+16=2(y+16)
x+16=2y+32
4y+16=2y+32 (using 1)
2y=16
y=8(age of son), x=4y=4×8=32(age of father)
present age of father is 32 years and present age of son is 8 years

Answer 2

let son age = x

man = 4x

after 16 years

2(x +16) = 4x +16
2x + 32 =4x + 16
2x - 4x = 16 - 32
-2x = -16
x = 8
 
son = 8 years  father = 4x =4*8 = 32years