Consider the Q and A. Q: Xavier needs 84 paper plates for a housewarming party. He already has 21 green plates and 28 red plates. How many more plates should Xavier buy?
A: 35
What is the step-by-step reasoning process?
Step-by-step reasoning process: The total number of green and red plates is 28 + 21 = 49. Xavier should buy 84 − 49 = 35 more plates.

Consider the Q and A. Q: It takes Jason 30 minutes to cut 1 lawn in his neighborhood. If he cuts 8 yards on both Saturday and Sunday, how many hours does he spend cutting grass?
A: 8
What is the step-by-step reasoning process?
Step-by-step reasoning process: He cuts 8 yards on both Saturday and Sunday so that’s 2 * 8 = 16 yards. It takes him 30 minutes to cut 1 yard so it takes him 30 * 16 = 480 minutes. There are 60 minutes in 1 hour and it takes him 480 minutes so that’s a total of 480 / 60 = 8 hours.

Consider the Q and A. Q: Martin spends 2 hours waiting in traffic, then four times that long trying to get off the freeway. How much time does he waste total?
A: 10
What is the step-by-step reasoning process?
Step-by-step reasoning process: First find the total amount of time he spends trying to get off the freeway: 2 hours * 4 = 8 hours. Then add the time he spends waiting in traffic to find the total time: 8 hours + 2 hours = 10 hours.

Consider the Q and A. Q: Chang's Garden has two kinds of apples. Sweet ones and sour ones. He can sell the sweet ones for $.5 an apple. The sour ones sell for $.1 an apple. 75% of the apples he gets are sweet and the rest are sour. If he earns $40, how many apples did his trees give him?
A: 100
What is the step-by-step reasoning process?
Step-by-step reasoning process:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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25% of the apples are sour because 100 - 75 = 25. The average price of an apple sold is $.4 because .75(.5) + .25(.1) = .4. He got 100 apples because 40 / .4 = 100.