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: two trains are moving in opposite directions at 60 km / hr and 90 km / hr. their lengths are 1.15 km and 0.6 km respectively. the time taken by the slower train to cross the faster train in seconds is ?
Options: a. 42, b. 9, c. 7, d. 67, e. 15
answer:
a


question:
Problem: find the simple interest on rs. 72,000 at 16 2 / 3 % per year for 9 months.
Options: a. 7500, b. 6500, c. 9000, d. 9500, e. none of them
answer:
c


question:
Problem: in a particular city there are 100 homes numbered from 1, 23,.., 100. the city was build by a builder from chennai. there was 4 to 5 shops in the town which was build by a builder from mumbai. the 2 nd builder can build in 1 ½ times as compared to time by 1 st builder. the 2 nd builder builds in 15 days, then how many 2 ' s are used by the builder from chennai in numbering the 100 homes ?
Options: a. 17, b. 18, c. 19, d. 20, e. 21
answer:

d