Question

It takes Jenny 8.4 minutes to sweep a porch.Mofor can sweep the same porch in 13.3minutes. If they worked together how longwould it take them?

Answer 1

Rate of Jenny = 1/ 8.4 minutes

Rate of Mofor = 1/13.3 minutes

We know time and rate are inverses of each other.

So, if they work together, their rates would be:

`(1)/(8.4)+(1)/(13.3)`

The time they will take will be the inverse of this, thus:

`((1)/(8.4)+(1)/(13.3))^(-1)`

So, let's calculate it:

`\begin{gathered} ((1)/(8.4)+(1)/(13.3))^(-1) \\ =5.1484 \end{gathered}`

That is around 5.15 minutes.