Two neighbors, wilma and betty, each have a swimming pool. both wilma's and betty's pools hold 9900 gallons of water. if wilma's garden hose fills at a rate of 900 gallons per hour while betty's garden hose fills at a rate of 500 gallons per hour, how much longer does it take betty to fill her pool than wilma?

To solve this problem we will start by calculating time needed for each of them to fill the pool.

We have formula:
Volume = rate * time
Or
time = volume / rate

Wilma:
time = 9900 / 900
time = 11h

Betty:
time = 9900 / 500
time = 19.8h

Now we substract these two numbers:
time_difference = 19.8 - 11 = 8.8h

Betty needs 8.8 hours more than Wilma to fill the pool.

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