Question

A monkey climbs 6 mts and falls 3mts in alternate minutes.Then time taken to climb a tree 60metres high?

Answer 1

Monkey would take 20 minutes to climb 60 Mt's tree

Answer 2

The monkey will need n forward steps and n-1 backward steps if you picturize that the monkey will need one extra forward step to reach the treetop. If that is the case then the following inequality will hold true.
$6n - 3(n - 1) \geqslant 60 \\ 3n + 3 \geqslant 60 \\ 3n \geqslant 57 \\ n \geqslant 19$
Therefore there will be 19 forward steps and 18 backward steps so the total minutes taken
$= 19 + 18 = 37$