Question

A monkey jumps 6 stairs forward and jumps backward 2 stairs at a time.
How many times monkey will jump to reach 100th stair without slipping backwards?Also, Is that number divisible by 5?

• A. Yes
• B. No
• C. $25$
• D. $17$

Answer 1

Answer: (A), (C)

$25$

At a single time Monkey jumps $6$ stairs forward and $2$ stairs backward.

Effective number of jumps in single time is $6-2=4$

So, for reaching to ${100}^{th}$ stair he will jump
$\frac{100}{4}=25\text{times}$.

And, Yes $25$ is divisible by $5$ because for a number to be divisible by $5$, number should have $0$ or $5$ at it's unit place.