You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
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Question: Question: Look at this series: 15, 15, 27, 27, 39, 39, 51, 51, 63, 63, ? ... What number should fill the blank?

 Option A: 51

 Option B: 39

 Option C: 75

 Option D: 15

 Option E: None

Answer: Option C


Question: Question: During the break of a football match, the coach will make 3 substitutions. If the team consists of 14 players among which there are 2 forwards, what is the probability that none of the forwards will be substituted?

 Option A:  21/55

 Option B:  18/44

 Option C:  21/99

 Option D:  28/44

 Option E:  36/55

Answer: Option C


Question: Question: A wheel that has 6 cogs is meshed with a larger wheel of 7 cogs. When the smaller wheel has made 21 revolutions, then the number of revolutions made by the larger wheel is:

 Option A: 9

 Option B: 10

 Option C: 6

 Option D: 18

 Option E: 7

Answer:
Option D