# Inverse proportion/Direct proportion question

• Sep 26th 2011, 05:57 AM
FailInMaths
Inverse proportion/Direct proportion question
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?
• Sep 26th 2011, 06:17 AM
Re: Inverse proportion/Direct proportion question
Quote:

Originally Posted by FailInMaths
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?

3 "identical" workers take 5 days to build 10 metres.
1 worker, working alone takes 3 times as long, that's 15 days for 10 metres,
which is 45 days for 30 metres.

5 workers take a fifth of the time.
• Sep 26th 2011, 06:31 AM
FailInMaths
Re: Inverse proportion/Direct proportion question
Quote:

3 "identical" workers take 5 days to build 10 metres.
1 worker, working alone takes 3 times as long, that's 15 days for 10 metres,
which is 45 days for 30 metres.

5 workers take a fifth of the time.

Oh, I get it now, I thought it required complex stuff for the solution, stupid me

Thanks =)
• Sep 26th 2011, 08:22 AM