The Lily Pad Pond

A lily pad doubles in size every day. If on the 60th day the pond is filled with the lily pad.

On what day is the pond only half covered?

Ah! Click here to read the solution.

The 59th day.

It doubles every day, and if the pond is half full on the 59th day, then it is filled on the 60th day. 🙂 Easy 😉

The Frog And 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?

Please Note: Assume after the first leap that his hind legs are exactly three meters up the well. His hind legs must clear the well for him to escape.

Ah! Click here to read the solution.

Each day he makes it up another meter, and then on the twenty seventh day he can leap three meters and climb out. 🙂