Guest Posted March 18, 2009 Report Share Posted March 18, 2009 Using only two jugs as measuring devices (one 3 gallon jug and one 5 gallon jug) and a supply of only 9 gallons of water, how can you get EXACTLY 4 gallons into one of the jugs? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 Using only two jugs as measuring devices (one 3 gallon jug and one 5 gallon jug) and a supply of only 9 gallons of water, how can you get EXACTLY 4 gallons into one of the jugs? Fill the 5 gallon jug, dump it out, then fill it with the remaining 4 gallons. There is a riddle like this that is very old. But your added constraint of there only being 9gallons makes it even easier. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 (edited) Let "S" be the nine gallon supply, "T" be three gallons, and "F" be five gallons... S T F 9 0 0 - Start 6 3 0 - Pour 3 into T 6 0 3 - Empty T into F 4 0 5 - Fill T from S -- Four gallons remaining in the S (supply) now to get it into one of the jugs... Edited March 18, 2009 by Scottie Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 Can we pour back into the "supply" ? Or is that even necessary to solve? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 (edited) Um, if your supply is exactly 9 gallons, then fill the 5 gallon jug once, dump it out and pour the remaining supply into it--you don't even need the 3 gallon jug...however, I don't think that is the answer you were looking for so... answer #2 fill both the 5 and 3 gallon jugs, dump out the 5, pour the 3 into the 5 and then add the remaining gallon of supply to the 5...again, this assumes a supply of exactly 9 gallons, so... answer #3 really, fill the 3, dump it into the 5. Fill the 3 again, dump what you can into the 5, leaving one gallon in the 3. Dump out the 5 and put the one gallon from the 3 into it. Fill the 3 again and add it to the one gallon already in the 5. Edited March 18, 2009 by BTH Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 (edited) Um, if your supply is exactly 9 gallons, then fill the 5 gallon jug once, dump it our and pour the remaining supply into it--you don't even need the 3 gallon jug...however, I don't think that is the answer you were looking for so... answer #2 fill both the 5 and 3 gallon jugs, dump out the 5, pour the 3 into the 5 and then add the remaining gallon of supply to the 5...again, this assumes a supply of exactly 9 gallons, so... answer #3 really, fill the 3, dump it into the 5. Fill the 3 again, dump what you can into the 5, leaving one in the 3. Dump out the 5 and put the one gallon from the 3 into it. Fill the 3 again and add it to the one gallon already in the 5. I assumed we couldn't discard extra water by dumping it out... but OP makes no mention of it. Silly me! Edited March 18, 2009 by Scottie Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 wasn't this posted b4?.. im not sure but i think this riddle was posted b4. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 Um, if your supply is exactly 9 gallons, then fill the 5 gallon jug once, dump it our and pour the remaining supply into it--you don't even need the 3 gallon jug...however, I don't think that is the answer you were looking for so... answer #2 fill both the 5 and 3 gallon jugs, dump out the 5, pour the 3 into the 5 and then add the remaining gallon of supply to the 5...again, this assumes a supply of exactly 9 gallons, so... answer #3 really, fill the 3, dump it into the 5. Fill the 3 again, dump what you can into the 5, leaving one in the 3. Dump out the 5 and put the one gallon from the 3 into it. Fill the 3 again and add it to the one gallon already in the 5. Yeeeaah this is the answer I was looking for... Your answer #3 is what I was looking for: "fill the 3, dump it into the 5. Fill the 3 again, dump what you can into the 5, leaving one in the 3. Dump out the 5 and put the one gallon from the 3 into it. Fill the 3 again and add it to the one gallon already in the 5" MAKING 4! I guess my wording should have been more specific. Whatever, it's what I could remember from Die Hard 3 Quote Link to comment Share on other sites More sharing options...
0 Guest Posted March 18, 2009 Report Share Posted March 18, 2009 (edited) Ahh...Die Hard 3...good times... Your wording was fine, I was just being stupid on purpose... Edited March 18, 2009 by BTH Quote Link to comment Share on other sites More sharing options...
0 rookie1ja Posted March 18, 2009 Report Share Posted March 18, 2009 Welcome to the Den, talon. There are many useful information about this forum in rules (see link "Important: READ BEFORE POSTING" at the top). For instance, perform a quick search before you post a riddle that you have not created. This way we ensure that you always get new riddles and don't have to see the same riddle each week. BTW, this is one of my favorite puzzles and I have dedicated 1 whole page to such weighing and measuring puzzles. Thread locked. Quote Link to comment Share on other sites More sharing options...
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Using only two jugs as measuring devices (one 3 gallon jug and one 5 gallon jug) and a supply of only 9 gallons of water, how can you get EXACTLY 4 gallons into one of the jugs?
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