A frog is at the bottom of a 30 meter well. Each day he summons enough energy for one 3 meter leap up the well.
Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards.
How many days does it take him to escape from the well?
Until the 27th night, the frog would have managed to scale a height of 1 meter per day or 27 meter in total.
On the 28th day, he would have climbed 3 meters during the day thereby completing his task.