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 grocer has a sale of rs. 5420, rs. 5660, rs. 6200, rs. 6350 and rs. 6500 for 5 consecutive months. find the sale he should have in the sixth month, so that he gets an average sale of rs. 6400 ?
Options: a. rs. 5870, b. rs. 8270, c. rs. 6020, d. rs. 6850, e. none of these

SOLUTION: b

PROBLEM: Problem: there is one 4 - digit whole number n, such that the last 4 digits of n 2 are in fact the original number n
Options: a. 8476, b. 7376, c. 9376, d. 7378, e. 9466

SOLUTION: c

PROBLEM: Problem: a windmill is taking advantage of strong air currents in order to produce electrical energy. on a typical day the wind speed is around 20 mph and in that speed the windmill produces 400 kw / h ( kilowatts per hour ). on a stormy day a windmill produces 20 % more energy. how much kw / h can 3 windmills produce in two hours on a stormy day ?
Options: a. 2880., b. 4860., c. 5780, d. 5760, e. 6380.

SOLUTION:
a