SOLUTION: A large pump can fill a water tank in 8 hours, and a smaller pump can fill it in 24 hours. In order to fill an empty tank, the small pump is operated for 6 hours, and then the larg

Question 1080404: A large pump can fill a water tank in 8 hours, and a smaller pump can fill it in 24 hours. In order to fill an empty tank, the small pump is operated for 6 hours, and then the large pump is also turned on. In total, how many hours will be required to fill the tank this way?
Answer by ikleyn(52754)   (Show Source): You can put this solution on YOUR website!
.
If you know the basics, you can solve everything.
If you don't know basics, there is nothing you can do.

To learn the basics, read these lessons explaining how to solve joint-work problems
    - 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".

---------------

Regarding your problem:

The rate of work of the large pump is : it fills  of the tank volume per hour.

The rate of work of the small pump is : it fills  of the tank volume per hour.

Their combined rate of work is  =  =  =  of the tank volume per hour.


After operating for 6 hours, the small pump filled  =  of the tank volume.

Hence, it will take  =  =  =  hours = 4 hours and 30 minutes for two pump to fill 
the remaining  of the tank volume working together.

Solved.

RELATED QUESTIONS
A large pump can fill a water tank in 6 hours, and a smaller pump can fill it in 10... (answered by lwsshak3,richwmiller)

Pump R can fill a tank in 8 hours and Pump Q can empty it in 12 hours. If both pumps are (answered by ikleyn)

A pump can fill an oil tank in 18 hours. Beginning with an empty tank, the pump and a... (answered by josgarithmetic)

A large pump can fill a tank in 28 minutes. Both a large pump and a small pump can fill a (answered by addingup,ikleyn)

An 8 hp pump can fill a tank in 8 hours. A smaller 3 hp pump fills the same tank in 12... (answered by drk)

Pump A can fill an empty 10,000 gallon tank in 4 hours, and auxiliary pump B can fill the (answered by ikleyn)

Pump A can fill a tank of water in 3 hours. Pump B can fill the same tank in 6 hours. How (answered by josgarithmetic,richwmiller)

Pump A can fill a tank in 10 hours. Pump B can empty the same tank in 15 hours. If both... (answered by ewatrrr)

One pump can fill a gas tank in 8 hours. With a second pump working simultaneously, the... (answered by ikleyn,greenestamps)