Question

An insect climb 2 cm up a slippery rod in one second and slips down by 1 cm over the next second.how mam y second will the insect take to reach the top of the rod 15 cm high

Answer 1

it is going through overall speed of 1cm/sec.
but after reaching at 13cm as it will climp 2cm it will be at top and it won't slip
so ans. is 14 sec.

Answer 2

An insect climb 2 cm up a slippery rod in one second and slips down by 1 cm over the next second. So it travels 1cm in 1 second.
Given insect climb 2 cm up a slippery rod in one second
So after reaching 13 cm it will climb 2 cm in 1 second It is the end point of the rod i.e., 15 cm .
So for climbing 13 cm it will take 13 seconds and to reach 2 cm more it takes one second more
 So total it takes 14 seconds to reach 15 cm