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.

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
c

Problem: two trains of equal are running on parallel lines in the same direction at 45 km / hr and 36 km / hr. the faster train passes the slower train in 36 sec. the length of each train is ?
Options: a. 45, b. 88, c. 66, d. 55, e. 22
a

Problem: a distributor sells a product through an on - line store, which take a commission of 20 % of the price set by the distributor. the distributor obtains the product from a producer at the price of $ 15 per item. what is the price that the buyer observers on - line if the distributor wants to maintain a 30 % profit on the cost of the item ?
Options: a. 18, b. 21.6, c. 22, d. 25.7, e. 27

d