Word Problem

Question

Mr. Powell can mow his lawn twice as fast as his son Rick can.  Together they di the job in 20 minutes.  How many minutes would it take Mr. Powell to do the job alone?

Answer 1

Let x = time (in minutes) it takes for Mr Powell alone

 

Then, 2x  = time (in minutes) it takes Rick alone

 

1/x = portion done by Mr Powell in one minute

 

1/(2x) = portion done by Rick in one minute

 

1/20 = portion done by both in 1 minute

 

So, 1/x + 1/(2x) = 1/20

 

Multiply by the LCD to get 20 + 10 = x

 

                                              x = 30 minutes

 

It takes Mr Powell 30 minutes to mow the lawn if he works by himself.