Simplify. 8(10m) 18m 810m 80 + m 80m

We know that there are 3,000 gallons in the swimming pool and that one hose filled it in x minutes (or hours, doesn't matter), while the second hose filled it 4x minutes. Together we have 5x (five parts that hoses have filled), so all we need to do is to divide 3,000 by 5:

3,000 ÷ 5 = 600

Now we can see that one hose filled 600 gallons, while the other one filled 4 * 600 = 2,400 gallons.