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: car z travels 50 miles per gallon of gasoline when driven at a constant rate of 45 miles per hour, but travels 20 percent fewer miles per gallon of gasoline when driven at a constant rate of 60 miles per hour. how many miles does car z travel on 10 gallons of gasoline when driven at a constant rate of 60 miles per hour ?
Options: a. 320, b. 375.2, c. 400, d. 408.3, e. 440

SOLUTION: c

PROBLEM: Problem: the average runs scored by a batsman in 30 matches is 50. in the next 15 matches the batsman scored an average of 26 runs. find his average in all the 45 matches ?
Options: a. 31, b. 42, c. 29, d. 97, e. 27

SOLUTION: b

PROBLEM: Problem: the market value of a certain machine decreased by 10 percent of its purchase price each year. if the machine was purchased in 1982 for its market value of $ 8000, what was its market value two years later ?
Options: a. $ 8,000, b. $ 5,600, c. $ 3,200, d. $ 6,400, e. $ 800

SOLUTION:
d