A monkey start climbing up a tree 17 ft tall.Each hour it hops 3 ft and slips back 2 ft. How much time would it take the monkey to reach the top.  Choose the correct choice from the following choices.
A) 15 hrs
B) 18 hrs
C) 19 hrs
D) 17 hrs
E) 16 hrs

Rationale: "if monkey hops 3 ft and slips back 2 ft in a hour , it means the monkey hops ( 3 ft - 2 ft ) = 1 ft / hr . similarly in 14 hrs it wil be 14 ft . bt since the height of the tree is 17 ft , so if the monkey hops up the tree in the next hr i . e 15 th hr then it reaches at the top of the tree . hence it takes 15 hrs for monkey to reach at the top answer : a"
Answer: A