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 probability of two events a and b are 0.25 and 0.40 respectively. the probability that both a and b occur is 0.15. the probability that neither a nor b occur is _________
Options: a. 0.45, b. 0.4, c. 0.5, d. 0.05, e. 0.6

Answer: c


Question: Problem: a 16 % stock yielding 10 % is quoted at :
Options: a. 83.33, b. 110, c. 112, d. 120, e. 160

Answer: e


Question: Problem: a trader bought a car at 20 % discount on its original price. he sold it at a 60 % increase on the price he bought it. what percent of profit did he make on the original price ?
Options: a. 28 %, b. 72 %, c. 12 %, d. 82 %, e. 16 %

Answer:
a