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: a student travels from his house to school at 12 km / hr and reaches school 2 hours late. the next day he travels 20 km / hr and reaches school 1 hour early. what is the distance between his house and the school ?
Options: a. 90, b. 100, c. 110, d. 120, e. 130
[A]: a


[Q]: Problem: what number must be added to 6, 16 and 8 to get an average of 13 ?
Options: a. 23, b. 22, c. 44, d. 33, e. 55
[A]: b


[Q]: Problem: the price of a bushel of corn is currently $ 3.20, and the price of a peck of wheat is $ 6.80. the price of corn is increasing at a constant rate of 5 x cents per day while the price of wheat is decreasing at a constant rate of x ( 2 ^ 1 / 2 ) - x cents per day. what is the approximate price when a bushel of corn costs the same amount as a peck of wheat ?
Options: a. $ 4.50, b. $ 5.10, c. $ 5.30, d. $ 5.50, e. $ 6.50
[A]:
e