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: a 270 metres long bullet train running at the speed of 120 kmph crosses another bullet train running in opposite direction at the speed of 80 kmph in 9 seconds. what is the length of the other bullet train ?
Options: a. 226, b. 230, c. 430, d. 310, e. 260
answer:
b


question:
Problem: if the average ( arithmetic mean ) of a and b is 45 and the average of b and c is 80, what is the value of c − a ?
Options: a. 25, b. 60, c. 90, d. 140, e. it can not be determined from the information given.
answer:
b


question:
Problem: the average height of 20 students in a class was calculated as 175 cm. it has later found that the height of one of the students in the class was incorrectly written as 151 cm whereas the actual height was 136 cm. what was the actual average height of the students in the class ?
Options: a. 174.75 cm, b. 174.25 cm, c. 173.75 cm, d. 173.25 cm, e. 172.75 cm
answer:

b