The present ratio of ages of A and B is 4:5. 18 years ago, this ratio was 11:16. Find the sum total of their present ages.

Explanation:-

Let present age of A and B be 4x and 5x.
18 years ago their ages;
^(4x-18)/_(5x-18) = ¹¹/₁₆;
Or, 64x-288 = 55x-198;
Or, 64x-55x = -198+288;
Or, 9x = 90;
Or, x = ⁹⁰/₉ = 10;
Sum of the present ages = 40+50 = 90 years.