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.

[EX Q]: Problem: a ( 3, w ^ 3 ) is the ( x, y ) coordinate of point located on the parabola y = x ^ 2 - 1. what is the value of w ?
Options: a. 2., b. 4., c. 5., d. 6., e. 9.
[EX A]: a

[EX Q]: 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
[EX A]: d

[EX Q]: Problem: the cost of a one - family home was $ 120,000 in 1980. in 1988, the price had increased to $ 180,000. what was the percent increase in the cost of the home ?
Options: a. 60 %, b. 50 %, c. 55 %, d. 40 %, e. 33.3 %
[EX A]:
b