instruction:
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.
question:
Problem: the first flight out of phoenix airport had a late departure. if the next 3 flights departed on - time, how many subsequent flights need to depart from phoenix on - time, for the airport ' s on - time departure rate to be higher than 40 % ?
Options: a. 4, b. 6, c. 5, d. 2, e. 8
answer:
d


question:
Problem: ages of two persons differ by 20 years. if 6 year ago, the elder one be 3 times as old the younger one, find their present age
Options: a. 12,28, b. 14,30, c. 16,36, d. 18,34, e. 19,34
answer:
c


question:
Problem: if a function f is defined by f ( x ) = - 1 / x for all non zero numbers x. if f ( a. = - 1 / 3 and f ( ab. = 1 / 6 then b = ?
Options: a. 2, b. 1 / 2, c. - 1 / 2, d. - 2, e. - 12
answer:

d