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.

Question: A and B together can do a work in 3 days. If A alone can do it in 12 days. In how many days can B alone do it?

 Option A: 4

 Option B: 6

 Option C: 8

 Option D: 10

 Option E: 25
Option A

Question: A businessman earns $28800 in December, thus decreasing his average annual (January to December) earnings by $1300. His average annual earnings would be
Source: CMAT Preparation

 Option A: $29000

 Option B: $33500

 Option C: $40200

 Option D: $41000

 Option E: $43100
Option E

Question: Rahul went to a shop and bought things worth Rs. 50, out of which 80 Paise went on sales tax on taxable purchases. If the tax rate was 8%, then what was the cost of the tax free items?

 Option A: 21.4

 Option B: 12.4

 Option C: 41.2

 Option D: 39.2

 Option E: 32.9

Option D