Eggs & Hourglasses (solution) When you drop the egg into the boiling water, start both glasses. After 7 minutes, when the 7-min glass stops, turn it over. After 11 minutes, when the 11-min glass stops, turn the 7-min glass again. When the 7-min glass runs out, 15 minutes will have passed. Back to "Eggs & Hourglasses" Back to riddle-page Homepage in English Homepage in Dutch