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.

Q: 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

A: Option C
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Q: Question: A 300 m long train crosses a platform in 33 sec while it crosses a signal pole in 18 sec. What is the length of the platform?

 Option A: 286 m

 Option B: 250 m

 Option C: 277 m

 Option D: 278 m

 Option E: 267 m

A: Option B
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Q: Question: A train 540 meters long is running with a speed of 54 kmph. The time taken by it to cross a tunnel 180 meters long is?

 Option A: 33

 Option B: 77

 Option C: 48

 Option D: 99

 Option E: 22

A:
Option C
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