<PRE><B>Question 191641</B>
Let x represent the amount of water the smaller pump can pump per hour.

The amount of water the larger pump can pump per hour is 77000/7 = 11000 gallons/h.

Working together the number of gallons of water they can pump each hour is
11000 + x.

As they can fill the reservoir in 6 hours, we have
6(11000+x)=77000
Solving for x, we have
11000 + x = 77000/6
x = 77000/6-11000
x = 77000/6-66000/6 = 11000/6

Therefore the amount of water the smaller pump can pump per hour is 11000/6.

So the time it takes for the smaller pump to fill the reservoir is

{{{77000/(11000/6)= 77000*6/11000= 42}}} hours.


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