How can an egg be boiled for 9 minutes using only a 4 minute hourglass timer and a 7 minute hourglass timer?
When the 4-min timer is empty for the second time, the 7-min timer has 1 minute worth of sand in the bottom half. Flip it over so there is now 1 minute in the top. When the 7-min timer empties, 9 minutes have elapsed.
How do you make a 9 minute egg?
Add water to your pot, keeping in mind that you only need enough to cover the eggs, and bring to a boil. Once you’re boiling, turn off the heat, add the eggs, cover and start your timer for nine minutes. A nine minute cook time is best for large eggs.
How do you make a 9 minute egg if all you have is a 4 minute and 7 minute egg timer?
Our Solution: The moment the 4-minute one runs out for the second time, turn the 7 minute hourglass over – it will have only been running exactly one minute. Let the sand run back again (1 minute more) and then take the eggs off straight away, because they will have boiled for 9 minutes.
How do you measure 15 minutes to boil an egg if there are 2 kinds of hourglass?
After it empties, turn the small glass, start boiling your eggs and continue watching the big glass. When, at the end of 11 minutes, the big one empties the small glass will be running for 4 minutes. Turn the big glass and wait another 11 minutes. 4 + 11 = 15.
How accurate can an hourglass be?
Hourglasses are aesthetically pleasing ornaments, rather than accurate timepieces – most of our hourglasses (except fillable ones) are accurate to within +/- 10%.
How do you make Martha Stewart hard-boiled eggs?
To hard-cook eggs, place them in a deep saucepan and cover with cold water by 1 inch. Bring to a boil over high heat, cover, remove from heat, and let stand 13 minutes. Use a slotted spoon to transfer eggs to an ice-water bath to stop the cooking. Serve warm, or leave in the bath to cool completely, about 10 minutes.
How do you boil eggs for 15 minutes?
What happens if you boil an egg for 15 minutes?
Hard-cooked (boiled) eggs – 19 minutes If you cook them for too long, the protein toughens (becomes rubbery) and a greenish or purplish ring forms around the yolk. Extremely fresh eggs are not recommended when making hard-boiled eggs, as they are very difficult to peel.
Can you run a 4 minute egg timer with a 7 minute timer?
We could for example start both timers together. When the 4 minute hourglass runs out we know that the 7 minute hourglass has run for 4 minutes also and so must have 4 minutes of sand in the bottom. If we flip it now it will necessarily run for 4 minutes. We already have a solution.
How long does it take to boil a 9 minute egg?
The trouble was not timing the egg, lots of people could handle that. The hard part was finding the shortest amount of time, which was as hard as this egg after boiling for nine minutes. We received (incorrect) answers as long as nearly a half hour. How long does the professor have to wait?
Can you add 2 minutes to the end of a 7 minute hourglass?
And there is a solution that allows this. We need to add 2 minutes on to the end of the 7 minute hourglass. Since the twice-flipped 4 minute hourglass will stop at 8 minutes we can flip our 7 minute hour glass here for the second time.
