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: How much time does a train 150 metres long running at 90 km/hr take to pass a pole?

 Option A: 7.9s

 Option B: 6s

 Option C: 7.5s

 Option D: 7.6s

 Option E: 7.4s
[A]: Option B


[Q]: Question: What does the hexa number E78 in radix 7.

 Option A: 12455

 Option B: 14153

 Option C: 14256

 Option D: 13541

 Option E: 14541
[A]: Option D


[Q]: Question: The cost to rent a small bus for a trip is x dollars, which is to be shared equally among the people taking the trip. If 5 people take the trip rather than 15, how many more dollars, in terms of x, will it cost per person?

 Option A:  x/6

 Option B:  x/16

 Option C:  x/40

 Option D:  3x/40

 Option E:  3x/22
[A]:
Option E