A, B and C are Accountants. A alone can file a return in 6 hours and B alone can file the same return in 10 hours. All three together can do it in 3 hours. In what time will C alone file the same return?
Answer
The correct answer is A: 15 hours. A's efficiency = 30/6 = 5 units/hr, B's = 30/10 = 3 units/hr. Together A+B+C = 30/3 = 10 units/hr.