Question

A monkey has to climb a pole of a height of 64 m. It can climb 8 m in 1st minute and comes down to 6 m in the 2nd minute. This process will be repeated till the monkey reaches the top. When monkey will climb on the pole?

1. 54 min
2. 57 min
3. 59 min
4. 56 min

Answer 1

Correct Answer - Option 2 : 57 min

Given:

A monkey has to climb a pole of a height of 64 m.

It can climb 8 m in 1st minute and comes down to 6 m in the 2nd minute.

This process will be repeated till the monkey reaches the top.

Concept used:

If the height of the pole is z meter and if a monkey climbs x meter in first min and y meter in second min and the process will be repeated till the monkey reaches the top, 

then we have to calculate first the required time in which it will climb (z - x) meter.

And to climb at the top, the total time the monkey will take {the required time in which it will climb (z - x) meter + 1}

Calculation:

For 1st min, he climbs 8 m and comes down 6 m in the 2nd min

Effectively he climbs 2 m in 2 min

It climbs in (28 × 2) mins = (2 × 28) m = 56 m

In 57th min monkey will climb the remaining 8 m.

That means, in 57 min, the monkey will climb at the top of the pole.

∴ In 57 min the monkey reaches the top of the pole.