In a certain village, n litres of water are required per household per month. At this rate, if there are m households in the village, how long (in months) will p litres of water last?  Choices:
A) p /m
B) P/mn
C) mp / n
D) np / m
E) npm
I find it much easier to understand with real numbers, so choose (almost) any numbers to replace m,n and p:   (p/m*n)   Answer (P/mn)
<result>B</result>
In a certain village, n litres of water are required per household per month. At this rate, if there are m households in the village, how long (in months) will p litres of water last?