Question

Calculate the Days to Escape From the Well
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?

Answer 1

I takes him 28 days because he moves 1 meter each day. On the 27th day, the frog will move tho the top of the well but will not get out and it will slide back down 2 meters to a 28 meters depth. On the 28th day, it will move to the 28+3=31st meter which is out of the well.