4. The sum of the reciprocals of Age pf Rehmanages, (in years) 3 years ago and 5 years from now is1/3Find his present age.

4. The sum of the reciprocals of Age pf Rehmanages, (in years) 3 years ago and 5 years from now is1/3Find his present age.

Let the present age pf Rehman = x years

Age of Rehman 3 years ago will =x - 3 years.

Age of Rehman 5 years from now will = x + 5 years.

Given that the sum of reciprocal is 1/3

Multiply by LCM of denominator 3(x-3)(x+5) we get 

3x +15 +3x – 9 = (x-3)(x+5)

6x +6 = x² + 5x - 3x – 15

6x + 6 = = x² + 2x – 15

0 = x² + 2x - 6x - 15 – 6

0 = x² - 4x – 21

Factorize it we get

-21= -7*3

And -7 + 3 = - 4  (middle term )

0 = x² - 7x + 3x – 21

0 = x(x - 7) + 3(x - 7)

0 = (x + 3) (x - 7)

x + 3 = 0 or x - 7 = 0

x = - 3 or x = 7
Since age cannot be negative.

so that x can not equal to - 3.

x is equal to 7.

present age of Rehman is 7 years.