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: Rahim bought 4 pillows with the average cost of $5. If Rahim also buys the fifth pillow with the price of $ 10, what is the average (arithmetic mean) price of those 5 pillows?

 Option A: $6

 Option B: $5

 Option C: $5.5

 Option D: $6.5

 Option E: $7

A: Option A
****
Q: Question: If one-third of one-fourth of a number is 15, then three-tenth of that number is

 Option A: 35

 Option B: 36

 Option C: 45

 Option D: 54

 Option E: 57

A: Option D
****
Q: Question: An unbiased die is tossed .find the probability of getting a multiple of 3

 Option A: 3/4

 Option B: 1/3

 Option C: 2/7

 Option D: 1/7

 Option E: 1/6

A:
Option B
****