WORD PROBLEM ON WORK

Question

5 Sam and Joey are hired for a project. After they work together for 2 hours, Sam leaves and Joey ?nishes the project in 3 more hours. Had Joey left instead of Sam, it would have taken Sam 4 more hours to ?nish the project. If none of them had left, how much time would they have needed to ?nish the project?

Answer 1

Hi Val,

 

OK,  we need to find out how long it will take them to finish if neither one left.

 

Joey can do the remaining work in 3 hours

 

Sam can do the remaining work in 4 hours

 

So in each hour Joey can do 1/3 of the remaining work

 

and Sam can do 1/4 of the remaining work

 

Let x equal the number of hours it will take them working together to finish the job

 

and the following equation can be used to solve for x

 

1 = x(1/3) + x(1/4)      

 

1 = x(4/12) + x(3/12)   (get common denominator to add fractions

 

1 = x(7/12)

 

12/7 = x     (it will take 1 and 5/7 hours for Sam and Joey to finish the job

 

Hope this helps

 

Tom