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?
28m 40sec
To find out at what time the monkey reached the top of the pole, we need to calculate how many minutes it takes for the monkey to complete a 30-meter ascent.
Let's break down the monkey's progress:
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.
In the fourth minute, the monkey descends 1 meter.
The monkey ascends 3 meters every 2 minutes since there is 1 minute of descent in between. Therefore, it takes the monkey 2 minutes to ascend a net distance of 2 meters (3 meters minus 1 meter).
We can now calculate the number of 2-minute intervals required for the monkey to reach the top of the pole. Since the monkey needs to ascend 30 meters, we divide 30 by 2:
30 meters ÷ 2 meters per 2 minutes = 15 intervals
Each interval takes 2 minutes, so we multiply the number of intervals by the duration of each interval:
15 intervals × 2 minutes per interval = 30 minutes
Therefore, the monkey reaches the top of the pole in 30 minutes.