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.
--------
Question: Question: A man can row a boat at 20 kmph in still water. If the speed of the stream is 6 kmph, what is the time taken to row a distance of 66 km downstream?

Option A: 30/83 hours

Option B: 33/13 hours

Option C: 31/13 hours

Option D: 30/13 hours

Option E: 30/14 hours

Answer: Option B

Question: Question: Three numbers are in the ratio 5 : 6 : 7. The sum of its longest and smallest numbers equals the sum of the third number and 54. Find the third number?

Option A: A

Option B: B

Option C: C

Option D: D

Option E: E

Answer: Option E

Question: Question: A began a business with Rs. 85,000. He was joined afterwards by B with Ks. 40,000. For how much period does B join, if the profits at the end of the year are divided in the ratio of 3 : 1 ?

Option A: 6.5 months

Option B: 3.5 months

Option C: 2.5 months

Option D: 8.5 months

Option E: 9.5 months

Answer:
Option D