SOLUTION: There are three small holes in a tub filled with water. If opened, hole one will empty the tub in 3 hours; hole 2 will empty the tub in 4 hours and hole 3 will empty the tub in 5

Question 1091142: There are three small holes in a tub filled with water. If opened, hole one will empty the tub in 3 hours; hole 2 will empty the tub in 4 hours and hole 3 will empty the tub in 5 hours. If all 3 holes are opened at the same time, how long will it take to empty the tub?
Answer by ikleyn(52775) (Show Source): You can put this solution on YOUR website!
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The rate of the hole/drain 1 of emptying the tank is  of the tank volume per hour.

The rate of the hole/drain 2 is  of the tank volume per hour.

The rate of the hole/drain 3 is  of the tank volume per hour.


When all 3 holes are opened (all three drains are turned ON), their combined rate is  =  =  of the tank volume per hour.


Hence, it will take   hours =   hours to empty the tank if all three holes are opened.

Solved.

It is a 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".

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