TASK DEFINITION: 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: Problem: when positive integer n is divided by 7, the remainder is 1. when n is divided by 11, the remainder is 5. what is the smallest positive integer k such that k + n is a multiple of 77 ?
Options: a. 2, b. 4, c. 6, d. 8, e. 10

SOLUTION: c

PROBLEM: Problem: a train 510 m long is running at a speed of 45 km / hr. in what time will it pass a bridge 140 m long ?
Options: a. 40, b. 52, c. 26, d. 21, e. 14

SOLUTION: b

PROBLEM: Problem: sarah is driving to the airport. after driving at 15 miles per hour for one hour, she realizes that if she continues at that same average rate she will be an hour late for her flight. she then travels 60 miles per hour for the rest of the trip, and arrives 30 minutes before her flight departs. how many miles did she drive in all ?
Options: a. 45, b. 175, c. 210, d. 245, e. 280

SOLUTION:
a