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.

Input: Consider Input: 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

Output: Option C


Input: Consider Input: Question: There is one highland where planes get fuel. A plan can cover the half of the world with full tank. A plane can transfer fuel from one plane to the other in the air. How many planes are required to make one plane cover the entire world once. Starting point of the travel is the Highland and coming back to the same Highland. All the other planes giving fuels to this Plane should also come back to the same highland and they don't have to cover the entire world.

 Option A: 2

 Option B: 3

 Option C: 4

 Option D: 5

 Option E: 6

Output: Option D


Input: Consider Input: Question: If seven machines working at the same rate can do 3/4 of a job in 30 minutes, how many minutes would it take two machines working at the same rate to do 3/5 of the job?

 Option A: 45

 Option B: 60

 Option C: 75

 Option D: 84

 Option E: 100


Output: Option D