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.

[Q]: Problem: what sum of money will produce rs. 80 as simple interest in 4 years at 3 1 / 2 percent ?
Options: a. 263, b. 571.4, c. 367, d. 368, e. 339
[A]: b


[Q]: Problem: a group of hikers is planning a trip that will take them up a mountain using one route and back down using another route. they plan to travel down the mountain at a rate of one and a half times the rate they will use on the way up, but the time each route will take is the same. if they will go up the mountain at a rate of 7 miles per day and it will take them two days, how many miles long is the route down the mountain ?
Options: a. 18, b. 19, c. 20, d. 21, e. 22
[A]: d


[Q]: Problem: 4 men and 3 women are lined up in a row. what is the number of cases where they stand with each other in turn ? ( the number of cases in which men ( or women ) do not stand next to each other )
Options: a. 12, b. 144, c. 18, d. 21, e. 24
[A]:
b