Solution Step 0/0
With a 7-minute hourglass and an 11-minute hourglass, what is the quickest way to time the boiling of an egg for fifteen minutes?
How many times during this time span the 7-minute hourglass is going to be turned over?
How many times during this time span the 7-minute hourglass is going to be turned over?
Explanations
Step 1. Start the 7- and 11-minute hourglasses when the egg is dropped into the boiling water.Step 2. When the sand stops running in the 7-glass, turn it over.
Step 3. When the sand stops in the 11-glass, turn the 7-glass again.
Step 4. When the sand stops running again in the 7-glass, 15 minutes will have elapsed.
Check 1 time
Check 2 times
Check 3 times
Check 4 times
