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: 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
Option B

Question: In the arithmetic sequence t1, t2, t3, ..., tn, t1=23 and tn= tn-1 - 3 for each n > 1. What is the value of n when tn = 8?

 Option A: -1

 Option B: 6

 Option C: 10

 Option D: 14

 Option E: 20
Option B

Question: In a division sum, the remainder is 0. As student mistook the divisor by 12 instead of 21 and obtained 35 as quotient. What is the correct quotient ?

 Option A: 19

 Option B: 20

 Option C: 21

 Option D: 23

 Option E: 25

Option B