In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake?

If a doctor gives you three pills, telling you to take one every half hour, how many minutes will pass from taking the first pill to the last pill?

An old auto is to drive a stretch of 2 miles, up and down a hill. Because the auto is so old, you cannot drive the first mile (the ascent) faster than 15 miles per hour.

How fast do you have to drive the second mile (going down the hill) in order to get an average speed of 30 miles per hour?

Once upon a time there was a beautiful princess named Anna. Anna’s father, the King, wanted to be sure his daughter married an intelligent man.

To test his daughter’s suitors the King hid Anna’s picture in one of three boxes. The suitor had to be able to select the box with Anna’s picture on one try and within twenty seconds.

The following messages were written on the boxes.

Gold box: Anna’s picture is in this box.
Silver box: Anna’s picture is not in this box.
Bronze box: Anna’s picture is not in the gold box.

The King would tell each suitor, “Only one of the three messages is correct.” Which box contained Anna’s picture?