You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

[Q]: Question: A and B complete a job in 6 days. A alone can do the job in 15 days. If B works alone, how many days will it take to complete the job?

 Option A: 8

 Option B: 10

 Option C: 12

 Option D: 14

 Option E: 16
[A]: Option B


[Q]: Question: How many odd 4-digit positive integers R that are multiples of 5 can be formed without using the digit 3?

 Option A: 648

 Option B: 729

 Option C: 900

 Option D: 1296

 Option E: 3240
[A]: Option A


[Q]: Question: an article with cost price of 180 is sold at 15% profit. what is the selling price?

 Option A: 198

 Option B: 200

 Option C: 204

 Option D: 207

 Option E: 210
[A]:
Option D


