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: two guys a and b leave point a and point b simultaneously and travel towards point b and point a on the same route at their respective constant speeds. they meet along the route and immediately proceed to their respective destinations in 32 minutes and 50 minutes respectively. how long will b take to cover the entire journey between point b and point a ?
Options: a. 65, b. 90, c. 70, d. 75, e. 80
[EX A]: b

[EX Q]: Problem: an investor deposited $ 10,000 to open a new savings account that earned 12 percent annual interest, compounded quarterly. if there were no other transactions in the account, what was the amount of money in the account 6 months after the account was opened ?
Options: a. $ 10,300, b. $ 10,303, c. $ 10,600, d. $ 10,609, e. $ 10,900
[EX A]: d

[EX Q]: Problem: the speed of a railway engine is 74 km per hour when no compartment is attached, and the reduction in speed is directly proportional to the square root of the number of compartments attached. if the speed of the train carried by this engine is 24 km per hour when 9 compartments are attached, the maximum number of compartments that can be carried by the engine is :
Options: a. 49, b. 18, c. 16, d. 17, e. 19
[EX A]:
e