Final answer:
To find 0.07 of 300 million gallons, you multiply 0.07 by 300,000,000 which equals 1. 21 million gallons, indicating a potential mistake with the question's options, as none of them is correct.
Step-by-step explanation:
The question at hand involves calculating a percentage of a given quantity. Specifically, the student is asking what 0.07 of 300 million gallons of water would be.
To find 0.07 of 300 million gallons, you multiply 0.07 by 300,000,000. This calculation will give you the amount of water in gallons that corresponds to the 0.07 part of the reservoir's capacity. So, the correct calculation would be:
0.07 * 300,000,000 gallons = 21,000,000 gallons
Therefore, 0.07 of Rexington reservoir's 300 million gallons would be 1. 21 million gallons, which is not one of the provided options. It seems there might be a mistake in the options provided in the question since the closest correct option in terms of order of magnitude would be 210,000 gallons, but this is still not the accurate answer.