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 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
Option D

Question: A certain sum earns simple interest of Rs. 800 in 2 years at a certain rate of interest. If the same sum earns compound interest of Rs.900in the same period of 2 years, What must be the rate of interest?

 Option A: 25%

 Option B: 10%

 Option C: 15%

 Option D: 20%

 Option E: 30%
Option A

Question: The speed of a boat in still water is 30kmph and the speed of the current is 15kmph. Find the speed downstream and upstream?

 Option A: 76,20 kmph

 Option B: 40,10 kmph

 Option C: 29 ,10,kmph

 Option D: 26,20 kmph

 Option E: 45,15 kmph

Option E