Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

[Q]: Problem: for each of her sales, a saleswoman receives a commission equal to 20 percent of the first $ 500 of the total amount of the sale, plus 35 percent of the total amount in excess of $ 500. if the total amount of one of her sales was $ 800, the saleswoman ’ s commission was approximately what percent of the total amount of the sale ?
Options: a. 22 %, b. 24 %, c. 25 %, d. 26 %, e. 28 %
[A]: d


[Q]: Problem: a copy machine, working at a constant rate, makes 35 copies per minute. a second copy machine, working at a constant rate, makes 65 copies per minute. working together at their respective rates, how many copies do the two machines make in half an hour ?
Options: a. 3,000, b. 2,700, c. 4,500, d. 5,400, e. 324,000
[A]: a


[Q]: Problem: if 8 gallons of gasoline are added to a tank that is already filled to 3 / 4 of its capacity, the tank is then filled to 9 / 10 of its capacity. how many gallons does the tank hold ?
Options: a. 20, b. 24, c. 36, d. 48, e. 60
[A]:
d