SOLUTION: There are 630 dishes that need to be rinsed. Ali can rinse them in 70 minutes by himself. It will take his friend Sam 105 minutes to rinse these dishes. How long will it take them

Question 1136313: There are 630 dishes that need to be rinsed. Ali can rinse them in 70 minutes by himself. It will take his friend Sam 105 minutes to rinse these dishes. How long will it take them if they rinse these 630 dishes together?

Answer by ikleyn(52812) (Show Source): You can put this solution on YOUR website!
.

Ali rinses  = 9 dishes in one minute (in each minute).


His friend rinses   = 6  dishes in one minute (in each minute).


Working together, they rinse  9 + 6 = 15 dishes per minute.


Hence, they will complete the job in   = 42 minutes, working together.

Solved   //   mentally.

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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
    - Special joint work problems that admit and require an alternative solution method (*)

Read them and get be trained in solving joint-work problems.
Pay special attention to the lesson marked (*) in the list, because it is most relevant to your problem.

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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