A tank can supply water to a village for 60 days. If a leak at the bottom of the tank drains out 10 liters per day, the supply lasts for 45 days only. For how many days will the supply last if the leak drains out 20 liters per day?
Answers:  A) 15  B) 18  C) 20  D) 24  E) 36

Rationale: losing 10 liters per day results in a loss of 450 liters in 45 days . so , those 450 liters were for 15 days , making daily consumption of the village 30 liters per day . thus the capacity of the tank is 30 * 60 = 1800 liters . losing 20 liters plus 30 liters gives 50 liters per day . at this rate the supply will last 1800 / 50 = 36 days . the answer is e .
Answer: E