TASK DEFINITION: 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.
PROBLEM: Problem: a man swims downstream 36 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water ?
Options: a. 7, b. 8, c. 9, d. 2, e. 4

SOLUTION: c

PROBLEM: Problem: the present population of a town is 2000. population increase rate is 20 % p. a. find the population of town after 1 years ?
Options: a. 1000, b. 2400, c. 1500, d. 1600, e. 1250

SOLUTION: b

PROBLEM: Problem: a number x is mistakenly divided by 10 instead of being multiplied by 10. what is the percentage error in the result ?
Options: a. - 99 %, b. - 100 %, c. + 99 %, d. + 100 %, e. none

SOLUTION:
a