2020 · Q125
Two years ago, the age of A was three times the age of B. If B is currently 9 years old, then after how many years, the age of A will be double the age of B?
general-mental-abilityquantitative-aptitude
- A2 years
- B3 years
- C4 years
- D5 years
Explanation
B is 9 now, so two years ago B was 7 and A was 3 × 7 = 21; A is therefore 23 now. Solving 23+t = 2(9+t) gives t = 5 — after 5 years A's age (28) will be double B's (14).