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.

[Q]: Problem: the h. c. f. of two numbers is 30 and the other two factors of their l. c. m. are 15 and 12. the larger of the two numbers is
Options: a. 476, b. 399, c. 450, d. 322, e. none
[A]: c


[Q]: Problem: sheila works 8 hours per day on monday, wednesday and friday, and 6 hours per day on tuesday and thursday. she does not work on saturday and sunday. she earns $ 360 per week. how much does she earn in dollars per hour ?
Options: a. 11, b. 10, c. 9, d. 8, e. 7
[A]: b


[Q]: Problem: two brothers ram and ravi appeared for an exam. the probability of selection of ram is 4 / 7 and that of ravi is 1 / 5. find the probability that both of them are selected.
Options: a. 4 / 35, b. 2 / 3, c. 7 / 35, d. 5 / 7, e. 7 / 5
[A]:
a