TASK DEFINITION: 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.
PROBLEM: Question: A die is rolled twice. What is the probability of getting a sum equal to 9?

 Option A: 2/3

 Option B: 2/9

 Option C: 1/3

 Option D: 1/9

 Option E: 1/10

SOLUTION: Option D

PROBLEM: Question: The time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream. If the speed of the boat in still water is 42 kmph, find the speed of the stream?

 Option A: 12

 Option B: 15

 Option C: 14

 Option D: 18

 Option E: 19

SOLUTION: Option C

PROBLEM: Question: One water pump can fill half of a certain empty tank in 7 hours. Another pump can fill half of the same tank in 7.5 hours. Working together, how long will it take these two pumps to fill the entire tank?

 Option A: 7 7/13

 Option B: 1 5/8

 Option C: 3 1/4

 Option D: 7 7/29

 Option E: 3 1/2

SOLUTION:
Option D