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Priyanka Mehta
CAT Preparation Community 10y ago
an ant climbing up a vertical pole ascends 12 metres and slips down 5 metre in every alternate hour. If the pole is 63metres high how long will it take it to reach the top
4
Pv Aaditya 10y ago
Hi,
Consider the first hour: the ant goes up by 12 m. It slips down by 5 m in the second hour. So, effective distance climbed in the first 2 hours = 7 m
So, in 14 hours, the ant would have climbed 7*7 = 49 m
In the 15th hour, it climbs to 61 m and in the 16th hour, it slips down to 56 m.
Now, there is only 7 m to get to the top of the pole. Since the ant covers 12 m in one hour, it covers 7 m in 35 minutes.
So, at the end of 16 hours 35 minutes, the ant would reach the top of the pole.
Sachinkumar Rajoria 7y ago
how did you get 35 minutes after 16 hr
?
Abhijeet Kumar 7y ago
Given,
Ant ascends 12 meters in first hours and slips down 5 meters in second hour. This is repeated in every alternate hour. (12 - 5 = 7 meters)
Therefore, in ends of 14 hours,
Ant ascends = (14 *7)/2 = 49 meters.
So, In next hour i.e 15 hour, Ant will ascends another 12 meter.
Till end of 15th hour, Ant climbed = 49 + 12 = 61 meters. But in 16th hour, Ant will slips down 5 meters (61 - 5 = 56 meters).
Remaining pole to climb,
63 - 56 = 7
Abhijeet Kumar 7y ago
After that, so the difference is 7 metre. In 60 minutes an ant climbes 12 min, by using unitary method it tooks 35 min to climb remaining 7 metre. So that total time it took is 16 hours 35 minutes.
Hope it clears 😊😊😊
