Riddle: You have 10 bags...

[ndee]

You have one scale and 10 bags with 100 coins each. 9 bags weigh 100g (gramms), 1 bag weighs 99g. With only one weighing, you have to find the bag which weighs 99g. How would you do it? Remember, you may use the scale only once. For example, you cannot put the first bag on the scale, read the weight, put the second one on the scale, read the weight, etc.
If you have the solution, please don't post it. If you have questions, just ask

BTW: Took me 20 minutes

 

[OulOat]

Clarification, what type of scale? The type you can only weigh on one side or is it both?

 

[ndee]

Originally posted by: OulOat
Clarification, what type of scale? The type you can only weigh on one side or is it both?

Ah, a one side scale. You can put something on the scale and read the weight.

 

[chuckywang]

I got the answer.

 

[Fritzo]

I must be sooper smart, because I figured it out in about 30 seconds. There's a very logical way to do it.

 

[her209]

Can you take coins out of the bag and put them into other bags?

 

[her209]

YHPM.

 

[JDub02]

got it

but if I can't post it, how is everyone supposed to know how 1337 I am?

 

[Gurck]

Since this is aimed at the average ATOTer - try desperately to lift each bag and fail - the one that budges ever so slightly is the 99g one

 

[JDub02]

.

 

[Murphy Durphy]

Put them on one at a time?

 

[dannybek2]

Originally posted by: Gurck
Since this is aimed at the average ATOTer - try desperately to lift each bag and fail - the one that budges ever so slightly is the 99g one

:thumbsup:

 

[dannybek2]

Originally posted by: HajikuFlip
Put them on one at a time?

Don't know if this is right, put them all on one time, remove one at a time until the value you remove is 1g less than the usual 10g.

 

[Raiden256]

Originally posted by: fiasco

Originally posted by: HajikuFlip
Put them on one at a time?

Don't know if this is right, put them all on one time, remove one at a time until the value you remove is 1g less than the usual 10g.

uh huh... that wasn't hard

 

[Gurck]

Originally posted by: fiasco

Originally posted by: HajikuFlip
Put them on one at a time?

Don't know if this is right, put them all on one time, remove one at a time until the value you remove is 1g less than the usual 10g.

Wouldn't removing each constitute a new use of the scale?

 

[Evadman]

Originally posted by: Gurck
Wouldn't removing each constitute a new use of the scale?

it does to me. That is 10 uses as far as I am concerned.

 

[jlee]

9 bags weigh 100g (gramms), 1 bag weighs 99g.

9 bags weigh 100g, or 9 bags weigh 100g each?

 

[daniel1113]

9 bags weigh 100g total (each coin weighs 1g).
1 bag weighs 99g total (each coin weighs 0.99g).

Good puzzle, btw. Took me a few minutes.

 

[b0mbrman]

Just pick them up and feel which one's the lightest...idiot :roll:

j/k

[Edit] Oh, and I got it

 

[ndee]

Originally posted by: her209
Can you take coins out of the bag and put them into other bags?

yes.

 

[ndee]

Originally posted by: fiasco

Originally posted by: HajikuFlip
Put them on one at a time?

Don't know if this is right, put them all on one time, remove one at a time until the value you remove is 1g less than the usual 10g.

you can't do that as I wrote in my example

 

[ndee]

Originally posted by: CadetLee

9 bags weigh 100g (gramms), 1 bag weighs 99g.

9 bags weigh 100g, or 9 bags weigh 100g each?

9 bags, each one weighs 100g, one bag weighs 99g. All bags together weigh 999g.

 

[se7en]

yeah took about 27.43 secs to think bout it.. ..

 

[ndee]

Solution as some have found:

Weigh one coin from the first bag, two coins from the second bag, three coins from the third bag, etc.
100 times the difference from 55 grams is the bag that weighs 99 grams.

copyright by chuckywang

 

[ndee]

Originally posted by: se7en
yeah took about 27.43 secs to think bout it.. ..

you cannot put all on the scale and then subtract them one after another. You may "read" the weight only once from the scale.