The price of 10 gallons of diesel fuel at the local gas station is D dollars. There are 128 fluid ounces in one gallon, and there are 100 cents in one dollar. What is the price, in cents, of 1000 fluid ounces of diesel fuel?

1. $latex \dfrac{D}{1280} &s=1$ (check answer)
2. $latex \dfrac{5D}{64} &s=1$ (check answer)
3. $latex \dfrac{25D}{32} &s=1$ (check answer)
4. $latex \dfrac{625D}{8} &s=1$ (check answer)
5. $latex 100D &s=1$ (check answer)

Solutions, hints, and questions are welcomed. A full solution will be posted on September 7th. If you would like to learn how to enter math formulas into this blog, visit the WordPress LaTeX tutorial page.

Hint for process of elimination: The problem asked for the price, in cents, of 1000 fluid ounces of diesel fuel. We are told in the problem, and you may also remember from science class, that there are 128 fluid ounces in one gallon. That means there are 1280 fluid ounces in ten gallons. 1000 ounces is a little less than ten gallons, but not much less. It follows that the price in dollars of the 1000 fluid ounces is a little less than $latex D &s=1$. Therefore, the price in cents of 1000 fluid ounces is a little less than $latex 100D &s=1$. The only answer with a coefficient of D that is close to but less than $latex 100 &s=1$ is choice D.

Read on for a full solution.

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