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 group of hikers is planning a trip that will take them up a mountain using one route and back down using another route. They plan to travel down the mountain at a rate of one and a half times the rate they will use on the way up, but the time each route will take is the same. If they will go up the mountain at a rate of 8 miles per day and it will take them two days, how many miles long is the route down the mountain?

 Option A: 18

 Option B: 20

 Option C: 22

 Option D: 24

 Option E: 25

A: Option D
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Q: Question: A code is to be made by arranging 9 letters. five of the letters used will be the letter A, two of the letters used will be the letter B, one of the letters used will be the letter C, and one of the letters used will be the letter D. If there is only one way to present each letter, how many different codes are possible?

 Option A: 42

 Option B: 210

 Option C: 46820

 Option D: 84002

 Option E: 90720

A: Option E
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Q: Question: Two trains are running in opposite directions with the same speed. If the length of each train is 180 m and they cross each other in 12 sec, then the speed of each train is?

 Option A: 54

 Option B: 77

 Option C: 36

 Option D: 88

 Option E: 21

A:
Option A
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