A is 6 years older than B. 10 years ago, B's age was three quarters of A's age. Find the present age (in years) of A.

Correct option is D

Given:

A is 6 years older than B → A = B + 6

10 years ago, B's age was $$\frac{3}{4}$$​ of A's age

Solution:
Let present age of B = x
Then present age of A = x + 6
10 years ago:

​$$x - 10 = \frac{3}{4} \times (x + 6 - 10) \\ \ \\x - 10 = \frac{3}{4}(x - 4)$$​​

4(x - 10) = 3(x - 4)

4x - 40 = 3x - 12

4x - 3x = -12 + 40

x = 28

Then:

A = x + 6 = 28 + 6 = 34 years