Question

Bob can paint a fence in 5 hours, and working with Jen, the two of them painted a fence in 2 hours. How long would it have taken Jen to paint the fence alone?

Answer 1

Answer:$\frac{10}{3}$

 

Step-by-step explanation:

Given

Bob can Paint a fence in 5 hr

so full job can be done in 5 hr

in 1 hr $\frac{1}{5}$ job is done

suppose Jen done the work in x hr

so in 1 hr $\frac{1}{x}$ part of job is done

Also if they combine they can do the job in 2 hr

so in 1 hr $\frac{1}{2}$

so $\frac{1}{5}+\frac{1}{x}=\frac{1}{2}$

$\frac{1}{x}=\frac{1}{2}-\frac{1}{5}$

$\frac{1}{x}=\frac{5-2}{10}$

$x=\frac{10}{3} hr$