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 lcm of two numbers is 2310 and hcf is 55. if one of the numbers is 210. then what is the other number ?
Options: a. 715, b. 825, c. 330, d. 605, e. 465

Answer: d

Question: Problem: if y > 0, ( 9 y ) / 20 + ( 3 y ) / 10 is what percent of y ?
Options: a. 40 %, b. 50 %, c. 60 %, d. 70 %, e. 75 %

Answer: e

Question: Problem: in a group of ducks and cows, the total number of legs are 40 more than twice the number of heads. find the total number of cows.
Options: a. 12, b. 14, c. 16, d. 18, e. 20

Answer:
e