Question

Usually, Dolores has to stock the shelves by herself and it takes her 7.2 hours. Today Camille helped Dolores and they were able to finish the task in 2.8 hours. How long would it have taken Camille if she were working alone?

Answer 1

It takes 4.58 hours to stock the shelves if Camille were working alone

Step-by-step explanation:

Let w be the work of stock the shelves and t be the time for Camille to the worl alone.

Dolores takes 7.2 hours.

$\texttt{Rate of Dolores = }\frac{w}{7.2}$

$\texttt{Rate of Camille = }\frac{w}{t}$

If they combine work is completed in 2.8 hours.

          That is

                       $2.8=\frac{w}{\frac{w}{7.2}+\frac{w}{t}}\\\\2.8=\frac{7.2t}{t+7.2}\\\\2.8t+20.16=7.2t\\\\4.4t=20.16\\\\t=4.58hours$

   It takes 4.58 hours to stock the shelves if Camille were working alone