A tank can supply water to a village for 20 days. If a leak at the bottom of the tank drains out 10 liters per day, the supply lasts for 15 days only. For how many days will the supply last if the leak drains out 20 liters per day?
Choose the correct choice from the following answers:	A) 9	B) 10	C) 11	D) 12	E) 14

Rationale: "losing 10 liters per day results in a loss of 150 liters in 15 days . so , those 150 liters were for 5 days , making daily consumption of the village 30 liters per day . thus the capacity of the tank is 30 * 20 = 600 liters . losing 20 liters plus 30 liters gives 50 liters per day . at this rate the supply will last 600 / 50 = 12 days . the answer is d ."
Answer: D