Question

The ratio of age of father to the age of son 5 years ago was 7 : 2 and the ratio of their age after 10 years
will be 2 : 1. Find the present age of father(in years).​

Answer 1

Answer:

Escape velocity is the minimum velocity that a body must attain to escape the gravitational field of the earth. Suppose if we throw a ball,it will fall back.

Answer 2

Let the present age of father and son is x and y respectively.

So 5 years ago,
7(x-5) = 2(y-5)
=> 7x - 35 = 2y - 10
=> 7x - 2y = 35 - 10 = 25. .….. (i)

10 years later,
2(x + 10) = y + 10
=> 2x + 20 = y + 10
=> 2x - y = -10 ……… (ii)

To solve equations (i) and (ii)
Multiply equation (ii) by 2 and subtract with equation (i)

7x - 2y = 25 …. (i)
4x - 2y = -20 ……… (ii)

(7 - 4)x - (2 - 2)y = 25+20
=> 3x = 45
=> x = 15

Therefore, substituting x in equation (ii)
30 - y = -10
=> 30 + 10 = y
=> y = 40

So father’s present age is 40 years.