SOLUTION: Marco can build a laptop twice as fast as Cliff. Working together, it takes them 5 hours. How long would it have taken Marco working alone?

Question 1080095: Marco can build a laptop twice as fast as Cliff. Working together, it takes them 5 hours. How long would it have taken Marco working alone?
Answer by ikleyn(52800) (Show Source): You can put this solution on YOUR website!
.

Let "m" be the Marco's rate of work.

Then Cliff's rate of work is , according to the condition.


Also, the condition says that 

 = ,

which means that  = ,   or    = ,  m = = .


Hence, It will take  = 7.5 hours for Marko to complete the job working alone.


Answer.  It will take 7 hours and 30 minutes for Marko to complete the job working alone.

There is a wide variety of similar solved joint-work problems with detailed explanations in this site. See the lessons
    - Using Fractions to solve word problems on joint work
    - Solving more complicated word problems on joint work
    - Using quadratic equations to solve word problems on joint work
    - Solving rate of work problem by reducing to a system of linear equations
    - Selected joint-work word problems from the archive
    - Joint-work problems for 3 participants
    - Had there were more workers, the job would be completed sooner
    - One unusual joint work problem

Read them and get be trained in solving joint-work problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Rate of work and joint work problems" of the section "Word problems".

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