instruction:
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: an optometrist charges $ 150 per pair for soft contact lenses and $ 85 per pair for hard contact lenses. last week she sold 5 more pairs of soft lenses than hard lenses. if her total sales for pairs of contact lenses last week were $ 1,220, what was the total number of pairs of contact lenses that she sold ?
Options: a. 9, b. 13, c. 15, d. 17, e. 19
answer:
a

question:
Problem: if the sides of a triangle are 26 cm, 24 cm and 15 cm, what is its area ?
Options: a. 120, b. 772, c. 180, d. 266, e. 2848
answer:
c

question:
Problem: for a certain art exhibit, a museum sold admission tickets to a group of 30 people every 5 minutes from 9: 00 in the morning to 4: 55 in the afternoon, inclusive. the price of a regular admission ticket was $ 10 and the price of a student ticket was $ 6. if on one day 3 times as many regular admission tickets were sold as student tickets, what was the total revenue from ticket sales that day ?
Options: a. $ 24960, b. $ 25920, c. $ 28080, d. $ 28500, e. $ 29160
answer:
b