Question

18 years ago the ratio of son's age to father's age was 8:13 the ratio of their present age is 5:7. what is the present age of the son?

Answer 1

LET SON BE A

LET FATHER BE B

now ACCORDING TO THE QUESTION,

Eighteen years ago the ratio of As age to B s age was 8:13.

Their present ratios are 5:7. What is the present age of A?

:

let x = the multiplier

then

5x = A's present age

and

7x = B's present age

:

18 years ago:

%28%285x-18%29%29%2F%28%287x-18%29%29 = 8%2F13

cross multiply

13(5x-18) = 8(7x-18)

65x - 234 = 56x - 144

65x - 56x = -144 + 234

9x = 90

x = 90/9

x = 10 is the multiplier

then

A = 5(10)

A = 50 yrs old now

:

:

Confirm this solution, find B's age; 10*7 = 70yrs old

%28%2850-18%29%29%2F%28%2870-18%29%29 = 32%2F52 = 8%2F13

Answer 2

Answer:

50 years

Explanation :

13(5x-18) = 8(7x-18)

65x - 234 = 56x - 144

65x - 56x = -144 + 234

9x = 90

x = 90/9

x = 10 is the multiplier

then

A = 5(10)

A = 50 yrs old now

and

find B's age; 10*7 = 70yrs old