Jane needs to bake a cake for her friends who are coming over any minute now. Due to an electric power failure Jane’s electric clock is no more working and she is using her gas oven. She had started baking the cake earlier and she needed to keep it in the oven for exactly 15 minutes more at the time of power outage. If cake is left any longer in the oven, it will burn.
Only thing Jane has for now to keep track of her time is a set of hourglasses, comprising of a 7-minute hourglass and an 11-minute hourglass. Sarah quickly figured out how to keep track of time with the help of hourglasses and exactly after 15 minutes she took out the cake that was very delicious.
Can you figure out how Jane managed to keep track of her time with the help of hourglasses?
——— View the answer ———
To bake a cake for 15 minutes, follow these four steps.
- Begin baking the cake and flip both hourglasses at the same time.
- When the 7-minute hourglass empties, flip it over to start it again.
- Four minutes after that when the 11-minute hourglass empties, flip the 7-minute hourglass once more.
- Let the 7-minute hourglass run out, which will take another 4 minutes and bring you to 15 minutes of baking time.
