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: In what time will a train 200 m long cross an electric pole, it its speed be 144 km/hr?

 Option A: 2 sec

 Option B: 2.7 sec

 Option C: 3.5 sec

 Option D: 5 sec

 Option E: 9.5 sec

A: Option D
****
Q: Question: The bankerâ€™s discount on Rs. 1600 at 10% per annum is the same as true discount on Rs. 1680 for the same time and at the same rate. The time is :

 Option A: 2 months

 Option B: 4 months

 Option C: 6 months

 Option D: 7 months

 Option E: None

A: Option C
****
Q: Question: A man’s speed with the current is 18 km/hr and the speed of the current is 2.5 km/hr. the man’s speed against the current is :

 Option A: 8.5 km/hr

 Option B: 9.5 km/hr

 Option C: 13 km/hr

 Option D: 12.5 km/hr

 Option E: None of these

A:
Option C
****