Question

A monkey standing on the ground wants to climb to the top of a vertical pole $13$ m tall. He climbs $5$ m in $1$ s and then slips downwards $3$ m in the next second. He again climbs $5$ m in $1$ s and slips by $3$ m in the next second as so on. How much time will the monkey take to reach the top of the pole?

• A. $7sec$
• B. $9sec$
• C. $11sec$
• D. $13sec$

Answer 1

The correct option is B $9sec$

The monkey takes 1 second to go up $5m$ and then, he comes down by $3m$ in next one second.
So, every $2sec$ he moves up by $2m$.
To move up $8m$, he will take $8sec$.
From $8m$ point, he will take one second to move another $5m$,

i.e., height of $8+5=$ $13m$. So, he has reached the top.
Hence, he reaches the top in $8s+1s=9s$.