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 takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. the ratio of the speed of the boat in still water and stream is
Options: a. 3: 1, b. 1: 3, c. 2: 4, d. 4: 2, e. none of these

SOLUTION: a

PROBLEM: Problem: what least number should be added to 1057, so that the sum is completely divisible by 23
Options: a. a. 4, b. b. 1, c. c. 2, d. d. 3, e. e. 5

SOLUTION: b

PROBLEM: Problem: what is the rate percent when the simple interest on rs. 800 amount to rs. 160 in 5 years ?
Options: a. 5 %, b. 7 %, c. 9 %, d. 2 %, e. 4 %

SOLUTION:
e