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: Two trains are moving at 60 kmph and 70 kmph in opposite directions. Their lengths are 150 m and 100 m respectively. The time they will take to pass each other completely is?

 Option A: 5 sec

 Option B: 6 sec

 Option C: 7 sec

 Option D: 8 sec

 Option E: 9 sec

Answer: Option C


Question: Question: John has only pennies, dimes, and nickels in a jar. The jar has at least 1 but no more than 4 pennies. If the jar has at least 1 nickel and 1 dime, which of the following could NOT be the total amount of money in the jar?

 Option A: 54

 Option B: 55

 Option C: 56

 Option D: 57

 Option E: 58

Answer: Option B


Question: Question: Which one of the following is not a prime number?

 Option A: 31

 Option B: 61

 Option C: 71

 Option D: 91

 Option E: 101

Answer:
Option D