Question

A monkey climbs 4 metres of a pole in 1 minute, but slips 2 metres in next minute, In how much time he will reach the top of a pole 15 meters long ? Assume that he starts from the bottom of the pole.

Answer 1

Monkey is at 0 meters at  0th minute.

time t = 0 minute,  height = 0  
    t = 1           height = 4 m
    t = 2        height = 4 - 2m = 2m
    t =3          h = 6 m
    t =4        h = 4 m

So after  t = 2 n minutes,  height = 2 n meters
check when the monkey will come with in  (15  - 4 ) = 11 meters.

so after t = 12 minutes,  height = 12 meters
then during  t  = 13 minutes,    monkey can climb 15 meters