An insect climbs 10m slippery rock in a minute and then slips down 9m in the next minute. How long will it take him to climb a 30m slippery rock?

Sorry by mistake,

Answer is 41 minutes not 21 minutes

21 minutes

To find out how long it will take the insect to climb a 30m slippery rock, we need to determine how many times the insect can climb up and slip down before reaching 30m.

In the first two minutes, the insect climbs 10m and then slips down 9m. This means it makes a net progress of 10m - 9m = 1m in 2 minutes.

So, for every 2 minutes, the insect climbs 1m in net progress.

To climb a 30m slippery rock, the insect needs to make a net progress of 30m. Since the insect climbs 1m in net progress in 2 minutes, we divide 30m by 1m to find the number of 2-minute intervals needed:

30m / 1m = 30

So it will take the insect 30 x 2 = 60 minutes to climb the 30m slippery rock.

the bug gains 1m each 2 minutes

after 20*2 minutes it has climbed 20 meters

During the 41st minute it climbs to 30m and is done.

1hour

30 minute

Dev kharbanda