Question

20 years later a man will be three times as old as he was 10 yr ago. How old he is now

Answer 1

Let x be the age of the person

20 years later his age will be thrice the age before 10 years. So

x+20=3(x-10)

2x=50

x=25

Answer 2

Let the present age of man = x years

20 years later, the man will be three times as old as he was 10 yr ago

x+20 = 3(x-10)

=> x + 20 = 3x - 30

=> x - 3x = -30 - 20

=> -2x = -50

=> 2x = 50

=> x = 50/2 = 25

Thus, the present age of the man is 25 years.