Correct Answer - Option 1 : 63 min
Given:
A monkey has to climb a pole of a height of 70 m.
It can climb 8 m in 1st minute and comes down 6 m in 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, 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 2nd min
Effectively he climbs 2 m in 2 min
It climbs in (31 × 2) mins = 2 × 31 = 62 m
In 63rd min monkey will climb remaining 8 m.
That means in total 63 min, monkey will climb at the top of the pole.
∴ In 63 min monkey reaches at the top of the pole.