A tank can supply water to a village for 100 days. If a leak at the bottom of the tank drains out 10 liters per day, the supply lasts for 75 days only. For how many days will the supply last if the leak drains out 20 liters per day? Select:
A) 50  B) 60  C) 65  D) 70  E) 72

Rationale: "losing 10 liters per day results in a loss of 750 liters in 75 days . so , those 750 liters were for 25 days , making daily consumption of the village 30 liters per day . thus the capacity of the tank is 30 * 100 = 3000 liters . losing 20 liters plus 30 liters gives 50 liters per day . at this rate the supply will last 3000 / 50 = 60 days . the answer is b ."
Answer: B