A monkey ascends a greased pole 30 m. high. He ascends 3 m. in Ist minute and descends 1m. in the next minute, again ascends 3m. in 3rd minute, but descends 1m. in 4th min and so on. In what time he reached the top?

To find out the time it takes for the monkey to reach the top of the pole, we need to analyze the pattern of its ascents and descents.

Let's break down the monkey's journey step by step:

In the first minute, the monkey ascends 3 meters.

In the second minute, the monkey descends 1 meter.

In the third minute, the monkey ascends 3 meters again.

In the fourth minute, the monkey descends 1 meter.

This pattern continues until the monkey reaches the top of the pole.

So, in every 2 minutes, the monkey covers a net distance of 3 - 1 = 2 meters.

To calculate how many times the monkey needs to go through this 2-minute cycle to reach the top, we divide the height of the pole (30 meters) by the distance covered in the 2-minute cycle (2 meters).

30 / 2 = 15

Therefore, the monkey needs to go through the 2-minute cycle 15 times to reach the top.

Since each cycle takes 2 minutes, we multiply 15 cycles by 2 minutes per cycle:

15 * 2 = 30

Hence, it will take the monkey a total of 30 minutes to reach the top of the pole.

every 2 minutes, the monkey gains 2m (up 3, down 1).

That's 1m/min, so after 28min he's 28m up.
On min 29 he makes it to the top.