Monkey ascending pole problem

A monkey tries to ascend a pole 20 metres high. He climbs 2 metres in the first minute and decends down 1 metre in the next minute. If this continues in this fashion, how long does he take to reach the top?

Solution:

First minute distance: 2 m

Second minute:  1 m descends.

Thus in 2 minutes he covers 2 – 1 = 1 m.

Since, 1 metre is covered in 2 minutes. 18 metres will be covered in 18 x 2 = 36 minutes.
Now in the next 37^th minute he will cover the remaining 2 metres and will reach the top of the pole.

Thus, it takes 37 minutes to reach the top of pole.

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Posted in: Distance Time n Speed