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: A fish can go upstream at 35 kmph and downstream at 55 kmph, and then find the speed of the fish in still water?

 Option A: 45

 Option B: 55

 Option C: 35

 Option D: 65

 Option E: 70

Answer: Option A


Question: Question: If one-third of one-fourth of a number is 15, then three-tenth of that number is

 Option A: 35

 Option B: 36

 Option C: 45

 Option D: 54

 Option E: 57

Answer: Option D


Question: Question: How many seconds will a 500 meter long train moving with a speed of 63 km/hr, take to cross a man walking with a speed of 3 km/hr in the direction of the train ?

 Option A: 15s

 Option B: 20s

 Option C: 25s

 Option D: 30s

 Option E: 35s

Answer:
Option D