Problema Solution

it takes 3hrs for 2 concrete mixers to mix a fixed amount of concrete. the number of hours varies inversely as the number of concrete mixers used. how long would it take 5 concrete mixers to do the same job?

Answer provided by our tutors

The number of concrete mixers used: N

The time: t

So the formula is

t = K/N

When t = 3, N=2, so K = 6

Wehn N = 5, t = 6/5 = 1.2

So it takes 1.2 hour for 5 concrete mixers to do the same job