Question: If 3 workers are required to build a 10m drain in 5 days, how many days will it take for 5 workers to build a 30m drain?
My first step is to calculate the inverse proportion of workers and days then I am stuck with the length of the drain. How do I go around to solve it?
You could formulate the problem also, using the concept of "man days".
It takes 5(3) "man days" to build 10 metres
so it takes 5(3)(3) = 5(9) "man days" to build 3(10) = 30 metres.
That shows straight off how many days are required for 5 men.