SOLUTION: The JUST-SAY-MOW lawn mowing company consists of two people: Marsha and Bob. If Marsha cuts the lawn by herself, she can do it in 3 hours. If Bob cuts the same lawn himself, it tak

Question 1120578: The JUST-SAY-MOW lawn mowing company consists of two people: Marsha and Bob. If Marsha cuts the lawn by herself, she can do it in 3 hours. If Bob cuts the same lawn himself, it takes him an hour longer than Marsha. How long would it take them if they worked together? Round to the nearest hundredth of an hour.
Answer by ikleyn(52781) (Show Source): You can put this solution on YOUR website!
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Marsha can do the job in 3 hours. She makes   of the job per hour. It is her rate of work.


Bob    can do the job in 4 hours. He  makes   of the job per hour. It is his rate of work.


Working together, they make   +  =  +  =  of the job per hour.


    (Their combined rate of work is the sum of individual rates.)


Hence, the time needed to complete the job for the two working together is   hours =   hours  

                                                                            = 1.714 hours = 1 hour and 43 minutes (approximately).

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It is a typical and standard 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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