In a certain village, 200 litres of water are required per household per month. At this rate, if there are 10 households in the village, how long (in months) will 2000 litres of water last? Select:  A) 1  B) 20  C) 2  D) 200  E) 2.5

Rationale: "i find it much easier to understand with real numbers , so choose ( almost ) any numbers to replace m , n and p : in a certain village , m 200 litres of water are required per household per month . at this rate , if there aren 10 households in the village , how long ( in months ) willp 2000 litres of water last ? water required is 200 * 10 = 2000 ( m * n ) water available is 2000 ( p ) it will last 1 months ( p / m * n ) answer ( a )"
Answer: A