A monkey starts climbing up a tree of 20 feet tall. Each hour it hops 3 feet and slips back 2 feet. How long monkey will take to reach the top of the tree?	Pick one:  A) 16 hours.  B) 19 hours.  C) 12 hours.  D) 18 hours.  E) 13 hours.
The monkey hops 3 feet and slips down 2 feet. So for the first hour it climb 1 feet.   Then for 2 hours 2 feet. Continuing the same till 17 hours, the monkey might have reached 17 feet.   In 18th hour monkey hops 3 feet and reach the 20 feet. Hence the answer is 18 hours.   Answer 18 hours.
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A monkey starts climbing up a tree of 20 feet tall. Each hour it hops 3 feet and slips back 2 feet. How long monkey will take to reach the top of the tree?