Question

The sum of father's age and twice the age of son is 70 if we double the age of father and add it to the son the sum of age is 95 .
Find their present age​

Answer 1

Answer:

* suppose age of father is x.

* age of son is y.

from first condition-

x + 2y = 70 : eqn 1st.

from second condition-

2x + y = 95 : eqn 2nd.

now add eqn 1st and 2nd.

x + 2y = 70

+

2x + y = 95

_______________

3x + 3y = 165

divide it by 3.

x + y = 55 : eqn. 3rd

now subtract eqn.1st from eqn.2nd

2x + y = 95

_

x + 2y = 70

__________

x - y = 25 : eqn.4th

add eqn.3rd and eqn.4th

x + y = 55

+

x - y = 25

___________

2x = 80

x = 80/2

x = 40

now put the value of x in eqn. 3rd

x + y = 55

40 + y = 55

y = 55 - 40

y = 15

hence:

present age of father = 40

present age of son = 15