Problems for Intermediate Methods in Theoretical Physics Edward F. Redish

Selling Gas

In the days leading up to hurricane Rita, people in the city of Houston evacuated.   A problem developed because some gas stations ran out of gas.   Estimate how much gas you think a typical gas station in College Park sells in one week. (Be sure to clearly state your assumptions and how you came to the numbers you estimated, since grading will be mostly based on your reasoning, not on your answer.)

Solution

I often stop in College Park to get gas. I note the following: the station I get gas at has 6 pumps. Typically, there are 1-3 other people stopping to get gas when I do. It takes about 5 minutes to fill my tank. I usually wait until I need about 12-15 gallons but I suspect that I other folks are more risk-averse than I am. I will assume a typical fillup is about 10 gallons. If I assume in the 5 minutes I am there that 2 people fill their tanks then in an hour my station will sell about (60/5)x2x10gals=240 gals in 1 hour. So in a 10 hour day, they would sell ~2400 gallons. I expect that in the evening and during the night, they will sell less -- say 1/2 as much. This means in the rest of the day (the remaining 14 hours) they would sell ~1200 gallons for a total of 3600. In one week this suggests a total of between 20,000 and 25,000 gallons.

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