#1

hahaha, i found this problem on a site. apparently its a 5th grade math class word problem. can you guys figure it out? it took me a while,

A very wealthy king has 8 bags of gold, which he trusts to some of his caretakers. All the bags have equal weight and contain the same amount of gold, all the gold in the kingdom. Although, the king heard a story that a woman received a gold coin. The king knew it had to be his gold so he wanted to find the lightest bag in the 3 weighings, but the mathematician thought it could be done in less, so I need to find out the least amount of weighing it takes to find the lightest bag. Also, the king used a pan balance for all of his weighing.

A very wealthy king has 8 bags of gold, which he trusts to some of his caretakers. All the bags have equal weight and contain the same amount of gold, all the gold in the kingdom. Although, the king heard a story that a woman received a gold coin. The king knew it had to be his gold so he wanted to find the lightest bag in the 3 weighings, but the mathematician thought it could be done in less, so I need to find out the least amount of weighing it takes to find the lightest bag. Also, the king used a pan balance for all of his weighing.

#2

Four on one side, four on the other.

#3

Four on one side, four on the other.

No thats not the answer. Well, its part to it at least, but not the whole thing. You have to figure out which bag of gold is that is not as heavy as the other ones.

#4

I know how to do it in three weighings. Not sure yet how you'd do it in less than that.

#5

wow, i'm glad i'm not in 5th grade anymore

#6

Four on one side, four on the other.

Then take the heavier side off, and do 2 per side withe the bags that were left on the lighter side. keep doing this till u have one bag,

#7

Then take the heavier side off, and do 2 per side withe the bags that were left on the lighter side. keep doing this till u have one bag,

but that would require at least 3 weighings

#8

If you want to do it in less than 3, you'd have to take a gamble.

Work out which is the lightest of the group of 4.

Then put 2 on the balance, one on each side.

If one is lighter, that's your bag, if they're the same, then you need to do the same with the other two.

Then you can work out which bag.

It's not guaranteed to work in two, but it's possible.

Work out which is the lightest of the group of 4.

Then put 2 on the balance, one on each side.

If one is lighter, that's your bag, if they're the same, then you need to do the same with the other two.

Then you can work out which bag.

It's not guaranteed to work in two, but it's possible.

#9

this is why i never did the hard questions in math

#10

Oh of course;

0 weighings.

He can just ask his caretakers

0 weighings.

He can just ask his caretakers

#11

Fifth grade sucked

#12

Why can't you just check inside the bags? This is a trick question, right?

#13

Like this:

3 bags on each side of the scale.

If one side is lighter than the other, you know the lightest bag is in that group.

If they are the same, you know the lightest bag is one of the two you didn't weigh.

If it's one of the two you didn't weigh, just see which one is lighter. It's that bag.

If it's in one of the groups of 3, put one bag on each side.

If they are the same, it is the bag you didn't weigh.

If they are different, it is the lighter bag.

tada!

3 bags on each side of the scale.

If one side is lighter than the other, you know the lightest bag is in that group.

If they are the same, you know the lightest bag is one of the two you didn't weigh.

If it's one of the two you didn't weigh, just see which one is lighter. It's that bag.

If it's in one of the groups of 3, put one bag on each side.

If they are the same, it is the bag you didn't weigh.

If they are different, it is the lighter bag.

tada!

#14

start with three bags on each side

if equal replace one bag on each side = lightest side light bag is the one you just replaced on that side

if unequal swap one bag from one side to the other and then replace one of the bags you didn't swap on each side if it is now equal light bag is the one removed from the light side if it is the same it is the bag you didn't touch on the light side if the scales change to the opposite of where you started the it is the bag you swapped from side to side

My brain hurts dont' do this no more

if equal replace one bag on each side = lightest side light bag is the one you just replaced on that side

if unequal swap one bag from one side to the other and then replace one of the bags you didn't swap on each side if it is now equal light bag is the one removed from the light side if it is the same it is the bag you didn't touch on the light side if the scales change to the opposite of where you started the it is the bag you swapped from side to side

My brain hurts dont' do this no more

#15

in the time it would have taken me to figure that out, i could have found that bag about 25 times

#16

All these ways to do it are stupid. Just do the goddamn 3 weighings, its much faster.

#17

you put 3 on each side, if they weigh the same you put the other 2 on each side and get the lightest.

if they don't weigh the same you put on two of the three lightest bags.

if they dont wiegh the same the third one is the lightest. and if they dont...you got it.

so you can do it in 2 weighings. yay!

if they don't weigh the same you put on two of the three lightest bags.

if they dont wiegh the same the third one is the lightest. and if they dont...you got it.

so you can do it in 2 weighings. yay!

#18

Ask the caretakers who gave the coin away?

#19

ok after reading all these suggestions and trying to come up with my own. i can safely say that fifth graders are a hell of a lot smarter than me

#20

Like this:

3 bags on each side of the scale.

If one side is lighter than the other, you know the lightest bag is in that group.

If they are the same, you know the lightest bag is one of the two you didn't weigh.

If it's one of the two you didn't weigh, just see which one is lighter. It's that bag.

If it's in one of the groups of 3, put one bag on each side.

If they are the same, it is the bag you didn't weigh.

If they are different, it is the lighter bag.

tada!

I knew it was something like that, and it still took me a good five minutes to figure it out...

#21

Why no, no I am not

#22

Like this:

3 bags on each side of the scale.

If one side is lighter than the other, you know the lightest bag is in that group.

If they are the same, you know the lightest bag is one of the two you didn't weigh.

If it's one of the two you didn't weigh, just see which one is lighter. It's that bag.

If it's in one of the groups of 3, put one bag on each side.

If they are the same, it is the bag you didn't weigh.

If they are different, it is the lighter bag.

tada!

Hot damn! These "fifth graders" must all be Asian...

#23

UG's not retarded, We're re-smarted!

#24

Nope. I'm not.

#25

I think the king should have the mathematician beheaded for being too smart.

#26

if i was in school and was trying to solve it i wouldve, but its a sunday and thinking is too much for me at the moment

#27

3 bags on each side of the scale.

If one side is lighter than the other, you know the lightest bag is in that group.

If they are the same, you know the lightest bag is one of the two you didn't weigh.

If it's one of the two you didn't weigh, just see which one is lighter. It's that bag.

If it's in one of the groups of 3, put one bag on each side.

If they are the same, it is the bag you didn't weigh.

If they are different, it is the lighter bag.

tada!

Touche.

#28

It's times like this that caused beheadings, so there'd be no need for a scale at all even.

Chop.

Chop.

#29

Anyone else think that's more of a riddle then a math problem?

i was thinking the same thing when i read it

#30

Dumbasses there all equal weight!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

#31

Dumbasses there all equal weight!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

at your stupidity

#32

4 bags on each side.

One will weight moe than the other (obviously)

all you need to do is swap 1 bag from each side over.

if you out 1234 on sideA and 5678 on sideB

Say side A is heavier.

swap bags 1 and 5, if the blanance changes then you know it was bag 5 that had the least amount of coins in because it was on the lighter side and if it had there would have been no change (obviously)

do it for bags 2 + 6 , 3 + 7

if it's none of those then you know it was either 4 or 8.

and in this case it will be 8 because side A is lighter and that is the only one that hasn't changed sides.

I'm not sure if thats right, I'm not the sharpest knife in the draw.

One will weight moe than the other (obviously)

all you need to do is swap 1 bag from each side over.

if you out 1234 on sideA and 5678 on sideB

Say side A is heavier.

swap bags 1 and 5, if the blanance changes then you know it was bag 5 that had the least amount of coins in because it was on the lighter side and if it had there would have been no change (obviously)

do it for bags 2 + 6 , 3 + 7

if it's none of those then you know it was either 4 or 8.

and in this case it will be 8 because side A is lighter and that is the only one that hasn't changed sides.

I'm not sure if thats right, I'm not the sharpest knife in the draw.

#33

Oh, what the ****? I'm an idiot

EDIT: Above comment for my stupid reasoning and inability to read the question.

EDIT: Above comment for my stupid reasoning and inability to read the question.

*Last edited by the_random_hero at Mar 12, 2007,*

#34

I didn't even understand the question.

#35

just because you cant answer this question doesnt mean your not smarter than a year 5 kid. Im sure only a skilled year 5er could do that shiz :P