Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
--------
Question: Problem: if 8 men or 12 women can do a piece of work in 30 days, in how many days can the same work be done by 6 men and 11 women ?
Options: a. 10 days, b. 11 days, c. 13 days, d. 15 days, e. 18 days

Answer: e


Question: Problem: two trains travel in opposite directions at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 8 seconds. the length of the faster train is
Options: a. 80 m, b. 100 m, c. 120 m, d. 180 m, e. 160 m

Answer: b


Question: Problem: the speed at which a man can row a boat in still water is 9 kmph. if he rows downstream, where the speed of current is 3 kmph, what time will he take to cover 60 metres ?
Options: a. 16 seconds, b. 34 seconds, c. 14 seconds, d. 18 seconds, e. 15 seconds

Answer:
d