SOLUTION: it takes Mary 4 hours to paint a room, John 5 hours to paint the room, and Jacob 6 hours to paint the room. How long will it take if they work together?

Question 1174038: it takes Mary 4 hours to paint a room, John 5 hours to paint the room, and Jacob 6 hours to paint the room. How long will it take if they work together?
Answer by ikleyn(52813) (Show Source): You can put this solution on YOUR website!
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The combined rate of work is    of the job per hour.


     = use the common denominator of 60 =  = .


It means that the three will complete the job in   hours, or in 1  hours = approximately 1 hour and 38 minutes.


I rounded the minutes to closest greater integer value.

Solved.

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It is a standard and typical joint work problem.

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
    - Selected joint-work word problems from the archive

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".

Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson

to your archive and use it when it is needed.

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