SOLUTION: Rahim can do certain work in 30 hours. If he and his son work together, the time taken is 20 hours. The son working in the same capacity as when he was working with his father, can

Question 1094827: Rahim can do certain work in 30 hours. If he and his son work together, the time taken is 20 hours. The son working in the same capacity as when he was working with his father, can finishing the work in
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39792)   (Show Source): You can put this solution on YOUR website!
If his son can do this one job in x hours, then , and the time for son to do one job alone, x, can be solved for.
.

Answer by ikleyn(53751)   (Show Source): You can put this solution on YOUR website!
.
Rahim can do certain work in 30 hours. If he and his son work together, the time taken is 20 hours.
The son working in the same capacity as when he was working with his father, can finishing the work in
~~~~~~~~~~~~~~~

Rahim's and his son's combined rate of work is of the job per hour. Rahim's individual rate of work is of the job per hour. Hence, the son's individual rate of work is the DIFFERENCE = = of the job per hour. Hence, it will take 60 hours for his son to complete the job working alone.

Solved.

Notice that there is NO NEED to solve any equations to get the answer.

All you need to know when solving such problems is THIS:

        1) the combined rate of work is the sum of rates of individuals;

        2) you should be able freely manipulate with fractions.

-------------------------------
It is 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
in this site.

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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