Hourglass Problem

Seize your precious time and don't let it slip away in the hourglasses! Your goal in this game is to measure 15 and 24 minutes by using a 7-minute and an 11-minute hourglass. You will be given the two hourglasses in the game, and you can click to reverse the hourglasses. The numbers at the top and the bottom of the hourglasses indicate the corresponding minutes in which the sand will flow. Click the Start button on the left of the screen when you are ready, and the sand in the hourglasses will start to descend from the top. When the sand in one of the hourglasses has run out, the other hourglass will stop. The minutes measured are shown at the bottom of the hourglasses as well as on the left of the screen. Then you may reverse the positions of the hourglasses again and continue the process, until the required minutes are measured. Take your time and make it count!