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: in what ratio must a grocer mix two varieties of pulses costing rs. 15 and rs. 20 per kg respectively so as to get a mixture worth rs. 16.50 per kg ?
Options: a. 3: 7, b. 5: 7, c. 7: 3, d. 7: 5, e. none
[A]: c


[Q]: Problem: a copy machine, working at a constant rate, makes 35 copies per minute. a second copy machine, working at a constant rate, makes 65 copies per minute. working together at their respective rates, how many copies do the two machines make in half an hour ?
Options: a. 3,000, b. 2,700, c. 4,500, d. 5,400, e. 324,000
[A]: a


[Q]: Problem: total dinning bill of 6 people was $ 139.00 and 10 % tip divided the bill evenly ? what is the bill amount each person shared.
Options: a. 21.84, b. 22.84, c. 23.84, d. 24.84, e. 25.48
[A]:
e