Sunday, October 24, 2010

025 - Blowout

Farmer Joe has 15 four-hour candles.

At 7 pm, Farmer Joe lights all his candles.

At 9 pm, he extinguishes one third of them.

At 10 pm, a breeze blows out half of those still burning.

At 11 pm, how many candles does Farmer Joe have left?