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.
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Question: Question: A tank holds x gallons of a saltwater solution that is 20% salt by volume. One Fourth of the water is evaporated, leaving all of the salt. When 5 Gallons of water and 10 gallons of salt are added, the resulting mixture is 33 1/3 % salt by volume. What is the value of x?

 Option A: 37.5

 Option B: 75

 Option C: 100

 Option D: 150

 Option E: 175

Answer: Option B


Question: 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

Answer: Option A


Question: Question: In a small snack shop, the average (arithmetic mean) revenue was $400 per day over a 10-day period. During this period, if the average daily revenue was $360 for the first 6 days, what was the average daily revenue for the last 4 days?

 Option A: $420

 Option B: $440

 Option C: $450

 Option D: $460

 Option E: $480

Answer:
Option D