A monkey start climbing up a tree 20ft tall.Each hour it hops 3 ft and slips back 2ft.How much time would it take the monkey to reach the top. 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 17 hrs it wil be 17 ft . bt since the height of the tree is 20 ft , so if the monkey hops up the tree in the next hr i . e 18 th hr then it reaches at the top of the tree . hence it takes 18 hrs for monkey to reach at the top answer : b
Answer: B