instruction:
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:
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
answer:
Option A


question:
Question: A certain population of bacteria doubles every 10 minutes. If the number of bacteria in the population initially was 10^5, then what was the number in the population 50 minutes later?

 Option A: 2(10^5

 Option B: 5(10^5

 Option C: (2^5

 Option D: (10^5

 Option E: (10^5
answer:
Option C


question:
Question: Diane find 1 can of paint are just enough to paint one third of her room. How many more cans of paint will she need to finish her room and paint a second room of the same size?

 Option A: 5

 Option B: 7 and a half

 Option C: 10

 Option D: 12 and a half

 Option E: 15
answer:

Option A