The ratio of present ages of A and B is 3:4. After 6 years, the ratio will be 4:5. What is A's present age?
Show answer & explanation
Correct answer: A
Explanation
Ratio of the present ages of A and B = 3 : 4
Ratio of ages after 6 years = 4 : 5
Present age of A = 3x years
Present age of B = 4x years
(3x + 6)/(4x + 6) = 4/5
5(3x + 6) = 4(4x + 6)
15x + 30 = 16x + 24
x = 6
Present age of A = 3 × 6 = 18 years