Hour glasses problem
March 24th, 2015 at 3:33:32 PM
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You have 3 hour glasses [but they aren't all for 1 hour]. One is for 5 minutes, the other is 7 minutes, and the other is 11 minutes. You have no perception of time, and have to go 100% from the glasses. In other words, you cannot estimate a glass is half full or 1/3 full or w/e.
You're out at a barbeque and want to cook hot dogs and hamburgers. You want to take them off at the same time so that no one is eating while others are waiting. You will cook the hot dogs for 4 minutes and hamburgers for 9 minutes. You only have one of each hourglass (5 min, 7 min, 11 min), but may use multiple times if you'd like (you don't have to use multiple times, though!).
For example, if I wanted to cook something for 16 minutes, I could use the 11 minute glass and once that one finished I'd flip over the 5 minute glass. Once the 5 minute glass has all the sand at the bottom, then 16 minutes will have elapsed.
As always, use spoilers for your answer(s).
You're out at a barbeque and want to cook hot dogs and hamburgers. You want to take them off at the same time so that no one is eating while others are waiting. You will cook the hot dogs for 4 minutes and hamburgers for 9 minutes. You only have one of each hourglass (5 min, 7 min, 11 min), but may use multiple times if you'd like (you don't have to use multiple times, though!).
For example, if I wanted to cook something for 16 minutes, I could use the 11 minute glass and once that one finished I'd flip over the 5 minute glass. Once the 5 minute glass has all the sand at the bottom, then 16 minutes will have elapsed.
As always, use spoilers for your answer(s).
March 24th, 2015 at 4:06:59 PM
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Start the 5 and 7, and start cooking the burgers.
When the 5 runs out, start the 11, and start cooking the hot dogs.
When the 7 runs out, the 11 has been running for two minutes; turn the 11 over.
When the 11 runs out, the burgers have cooked for 9 minutes, and the hot dogs for 4, in 9 minutes.
March 24th, 2015 at 4:28:51 PM
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- Start the 5 and 7.
- When the 5 runs out, start the 11.
- When the 7 runs out, the 11 has 9 min left. Put on your hamburger and start the 5.
- When the 5 runs out, the 11 has 4 min left. Put on your hot dogs.
- When the 11 runs out, everything is done.
March 24th, 2015 at 4:36:16 PM
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I think ThatDonGuy's answer is better than mine because it gets everything done quicker. My answer works with any timing device though, not just hour glasses.
March 24th, 2015 at 5:14:59 PM
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Time = 0: Flip the 5 and 7 minute timers.
Time = 5 (when 5-minute timer runs out): Flip the 11 minute timer.
Time = 7 (when 7-minute timer runs out): Flip the 5-minute timer, and put on the burgers.
Time =12 (when 5-minute timer runs out): Put on hot dogs.
Time = 16 (when the 11-minute timer runs out): Eat!
My compliments to ThatDonGuy, who accomplished the same thing in less time.
"For with much wisdom comes much sorrow." -- Ecclesiastes 1:18 (NIV)
March 24th, 2015 at 6:48:48 PM
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deleted, misread the problem
So many better men, a few of them friends, are dead. And a thousand thousand slimy things live on, and so do I.
March 25th, 2015 at 3:22:07 AM
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Hi!
It can be done with only two of the hourglasses
Flip 5 and 7
When 5 is done start with burgers and flip 5 again.
When 7 is done flip it again
When 5 is done start with hot dogs
When 7 is done after 14 minutes meal is ready
It can be done with only two of the hourglasses
Flip 5 and 7
When 5 is done start with burgers and flip 5 again.
When 7 is done flip it again
When 5 is done start with hot dogs
When 7 is done after 14 minutes meal is ready
