Work problems can be express as :
[tex](\frac{1}{a}+\frac{1}{b})t=1[/tex]where a and b are the rates of two person doing one work
and
t = time to finish the work when working together.
From the problem, Joan takes two times longer than Jane.
If Jane can file the report in x minutes, Joan will be 2x minutes.
They can file the report together in 6 minutes so t = 6
Plug in the values to the equation :
[tex](\frac{1}{x}+\frac{1}{2x})\times6=1[/tex]Simplify then solve for x :
[tex]\begin{gathered} (\frac{1}{x}+\frac{1}{2x})\times6=1 \\ \text{Multiply both sides by 2x} \\ 2x\times(\frac{1}{x}+\frac{1}{2x})\times6=2x\times1 \\ (2+1)\times6=2x \\ 3\times6=2x \\ 18=2x\text{ } \\ x=\frac{18}{2}=9 \end{gathered}[/tex]x = 9, so Jane can file the report in 9 minutes.
Since Joan is two times longer than Jane, she can file the report in 18 minutes.
Answers :
Jane = 9 minutes
Joan = 18