3 ms·

success is saying "eyeball the sand in the 7-minute hourglass and see when it looks like 1 minute worth?"

• masswerk 3y ago
  It's just missing a few steps: First, remove the end from the lower (still empty) half of 7-minute hourglass, causing it to drain its sand, while it runs. When the 7-minute hourglass runs out, do the same with the 4-minute hourglass (being on its second run). Flip the (now empty) 7-minute hourglass over and let the rest of the 4-minute hourglass drain into this. As the latter runs out, flip the 7-minute hourglass for 1 minute worth of accumulated sand (minus a few grains lost over handling procedures). ;-)
• xianshou 3y ago
  No, this is precisely correct. To simplify further: 1. Start H4 and H7 2. Flip H4 when it runs out (4-minute mark) 3. Flip H7 when it runs out (7-minute mark, 1 minute left on H4) 4. Flip H7 back when H4 runs out again (8-minute mark, 1 minute elapsed on H7) 5. When H7 runs out again (after 1 minute), exactly 9 minutes have passed
  • sterlind 3y ago
    Your summary is incorrect. Step 3 doesn't match what GPT-4 actually said: > When the 7-minute hourglass runs out, don't flip it yet, but note that the 4-minute hourglass has now been running for 3 minutes on its second run. (This marks 7 minutes.) When the 4-minute hourglass runs out again, flip the 7-minute hourglass. (This marks 8 minutes.) Notice that GPT-4 says not to flip H7 when it runs out, which is a mistake.
• deleted 3y ago
  [deleted]