Given are 12 marbles. One of these marbles is slightly heavier or lighter than the others. You have two plate scales. You are allowed to weigh three times. Can you find the marble that differs in weight?
Heres another
A farmer is standing on one side of the river and wtih him is a wolf, a goat, and a box with cabbage. In the river is a small boat. The farmer wants to cross the river with all the thrww items who are with him. There are no bridges and in the boati there is only room for the farmer and one item. But if he leaves the goat with the cabbages alone on one side of the river the goat will eat the cabbages. If he leaves the wolf alone with the goat the wolf will eat the goat. Only teh farmer can seperate the wolf from the goat and the goat from the cabbage. How can the farmer cross the river with all three items, without one eating the other?
2006-08-24 12:11:32 · 14 answers · asked by Christina B 2 in Social Science ➔ Psychology
Heres another.
U2 has a concert they must all cross a bridge to get there. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people must have the flashlight with them. The flashlight must be walked back and forth; it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower mans pace:
Bono:1 minute to cross
Edge:2 min
Adam:5 min
Larry:10 min
What is the shortest amount of time they can use to cross the bridge?
2006-08-24 12:31:32 · update #1
Scales: Weigh 6 marbles on one scale, 6 on the other.
One scale with 6 marbles will show more weight than the other. Take those 6 marbles, put 3 on one scale and 3 on the other.
One scale with 3 marbles will show more weight than the other.
Take those 3 marbles, put 1 on one scale and 1 on the other.
The scale that shows more weight has the heavy marble.
If they both weigh the same, the it's the marble you didn't weigh that's the heaviest.
Farmer takes the goat across, comes back for the wolf. Takes the wolf across and brings back the goat. Leaves the goat, takes the cabbage across and leaves them with the wolf. Then he comes back for the goat.
2006-08-24 12:18:26 · answer #1 · answered by Anonymous · 1⤊ 0⤋
For the farmer wolf/goat/cabbage one, which I am familiar with (although I know it as fox/goose/grain),
First the farmer takes over the goat, then the farmer goes back. Then he takes over the wolf, and on the return trip, takes the goat back. Then he takes over the grain. So on the side he wants to get to is the wolf and the grain, with the goat remaining. Finally, the farmer takes over the goat.
Could you please explain out the first one better? Are you sure that one marble is slightly heavier or lighter, not just heavier, or just lighter? What do you mean that you have 'two plate scales'. Do you mean that you have two scales with plates, or a scale that has two plates on it?
2006-08-24 12:21:56 · answer #2 · answered by TwilightWalker97 4 · 0⤊ 1⤋
First take the goat over the river, leaving the wolf and the cabbage. Then you go back and get the wolf and drop him off and pick up the goat (leaving the wolf alone), and take him back to the other side. Drop off the goat and pick up the cabbage, take the cabbage across and leave it with the wolf, then go back and get the goat.
2006-08-24 12:21:11 · answer #3 · answered by ~~~ 1 · 1⤊ 0⤋
The farmer can cross first with the goat and leave it on the other side. Then he can cross with the cabbage. On his way back from dropping off the cabbage, he takes the goat back with him. He leaves it on the other side, and brings the wolf to the side with the cabbage. Then he goes back and brings the goat.
2006-08-24 12:17:52 · answer #4 · answered by Kiki 6 · 1⤊ 0⤋
1) first you weigh six marbles on each side, to determine which group of six has the unequal marble. Then, of those six, weigh three on each side, to determine the group of three that has the unequal marble. Then weigh one of the three on each side. If the scales are equal, then the one you didn't weigh is the unequal one.
2) Take the goat across. Go back, get the wolf, and take it across. Take the goat back with you, and take the cabbage to the side with the wolf. then go back and get the goat.
I'm not sure if the first one's right, but I know the second one is.
2006-08-24 12:24:43 · answer #5 · answered by Crys H. 4 · 1⤊ 0⤋
He should take the goat, go back for the cabbage, drop off the cabbage and take the goat back, take the wolf, then go back once more for the goat.
2006-08-24 12:18:33 · answer #6 · answered by Maya M 2 · 1⤊ 0⤋
To your second riddle:
The farmer takes the goat over first and then comes back alone. Then, he takes the cabbages over and comes back with the goat. Then, he takes the wolf over and comes back alone. Then, he takes the goat over.
2006-08-24 12:59:32 · answer #7 · answered by Anonymous · 1⤊ 0⤋
still working on them.....
Marbles
One marble is heavier.
Weigh 4 on one plate, 4 on the other, leave 4 unweighed.
If the scales balance, then discard all 8 and use the 4 unweighed marbles.
If the scales don't balance, discard the unweighed marbles and the 4 lighter marbles.
You are left with 4 marbles, put 2 on each plate - discard the lighter 2, then put one on each plate, the heavier marble is the one!!!!
Can't work it out yet if it is unknown whether the marble is heavier or lighter.
2006-08-28 11:37:04 · answer #8 · answered by sheila 3 · 1⤊ 0⤋
about the farmer
he should be holding the cabbage letssay on hes lap so he could always prevent the goat from eating it
let the wolf swim
and the goat in the boat
2006-08-25 04:41:55 · answer #9 · answered by Anonymous · 0⤊ 1⤋
The farmer eats the cabbage, and then takes the wolf and the sheep over one at a time. Technically then he will be bringing the cabbage over, but it will be inside of him.
2006-08-24 12:17:42 · answer #10 · answered by tmess9 2 · 0⤊ 1⤋