Answer the following question.
Bob and Jim decide to skip rocks. Bob can skip a rock 12 times. Jim can skip a rock 15 times. If they each skipped 10 rocks how many total skips did they get?
Step-by-step reasoning process: Bob got 12 * 10 = 120 skips. Jim got 15 * 10 = 150 skips. So in total they got 120 + 150 = 270 skips.
The answer is 270.

Answer the following question.
Joan has 2 hours to get all her music practice done. She spends 30 minutes on the piano, 25 minutes writing music on her computer, and 38 minutes reading about the history of the piano. Her final work is to use a special finger exerciser. How much time does she have left to use this?
Step-by-step reasoning process: She has 120 minutes to practice because 2 x 60 = 120. She has already spent 93 minutes on her work because 30 + 25 + 38 = 93. She has 27 minutes to use on finger exercise because 120 - 93 = 27.
The answer is 27.

Answer the following question.
Ian spent half the money he made on doing online surveys. If he worked 8 hours doing surveys and on average he's able to earn $18 per hour doing surveys, how much money does he have left?
Step-by-step reasoning process: Ian is able to earn $18 per hour doing surveys. If he worked 8 hours doing surveys, then he earned $18 * 8 = $144. If he spent half of what he earned, then he spent $144 * 50% = $72. If Ian spent $72 of his earnings, then he has $144 - $72 = $72 left.
The answer is 72.

Answer the following question.
The class has to guess how many jellybeans are in a jar the teacher brought in. He lets 4 students make their guesses. The first thinks it contains 100 jellybeans. The second says there are 8 times as many. The third guesses 200 less than the third. The fourth takes the average of the first three guesses, and then adds 25 to it. How many jellybeans did the fourth student guess?

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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Step-by-step reasoning process: The second student guessed 800 because 8 x 100 = 800. The third guessed 600 because 800 - 200 = 600. The total guesses of the first three is 1500 because 100 + 800 + 600 = 1500. The average of the first three guesses is 500 because 1500 / 3 = 500. The fourth student guessed 525 because 500 + 25 = 525.
The answer is 525.