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: A man rows to a place 48 km distant and come back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is:

 Option A: 2 km/hr

 Option B: 1 km/hr

 Option C: 4 km/hr

 Option D: 6 km/hr

 Option E: 5 km/hr

Answer: Option B


Question: Question: In a class of 40 students, 10 did not opt for math. 15 did not opt for science and 2 did not opt for either. How many students of the class opted for both math and science?

 Option A: 13

 Option B: 15

 Option C: 7

 Option D: 17

 Option E: 18

Answer: Option C


Question: Question: The average marks of a class of 35 students is 45 and that of another class of 55 students is 65. Find the average marks of all the students?

 Option A: 52.6

 Option B: 52.4

 Option C: 52.1

 Option D: 57

 Option E: 52.9

Answer:
Option D