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’s speed with the current is 18 km/hr and the speed of the current is 2.5 km/hr. the man’s speed against the current is :

 Option A: 8.5 km/hr

 Option B: 9.5 km/hr

 Option C: 13 km/hr

 Option D: 12.5 km/hr

 Option E: None of these

Answer: Option C


Question: Question: A is twice as fast as B. If B alone can do a piece of work in 18 days, in what time can A and B together complete the work?

 Option A: 10

 Option B: 16

 Option C: 18

 Option D: 6

 Option E: 12

Answer: Option D


Question: Question: A and B complete a job in 6 days. A alone can do the job in 24 days. If B works alone, how many days will it take to complete the job?

 Option A: 8

 Option B: 9

 Option C: 10

 Option D: 11

 Option E: 12

Answer:
Option A