Question

The ratio of the ages of A and B seven years ago was 3 : 4 respectively. The ratio of their ages nine years from now will be 7 : 8 respectively.

Answer 1

Answer:

Step-by-step explanation:

Let the present age of A and B be a and b respectively

a-7 : b-7 = 3 : 4

4a - 28 = 3b - 21

4a - 3b = 7                     - 1

8a - 6b = 14                    - 2

a+9 : b+9 = 7:8

8a + 72 = 7b + 63

8a - 7b = - 9                 - 3

Subtracting eqn 3 from 2,

8a - 6b = 14

8a - 7b = -9

-6b + 7b = 14 + 9

b = 23

Substituting in eqn 1

4a - 3x23 = 7

4a = 7 + 69

a = 76/4

a = 19

So, present age of A is 19 and that of B is 23

Hope for brainliest!!!!