IQ question!

[Cheesetian]

Here's one for you guys.

I have 10 packets of beans. In each packet there are 10 beans. 1 packet contains 10 beans that weigh 1.1g each while the remaining 9 packets also contain 10 beans each but they each only weigh 1g. Now here's the tricky part. I need to find out which packet is the one with the beans that weigh 1.1g each. I have a weighing machine but i'm only allowed ONE reading. I'm not allowed to weigh the bags/beans individually meaning with just one reading from this weighing machine, i should be able to find out from which bag the 1.1g beans originate from.

I hope my explanation was clear enough. I've got the answer but let's see how good you guys are.

 

[Younglin]

Label the bags from 1 to 10. Take 1 bean out of Bag 1 and label it 1. Take 2 beads out of Bag 2 and label them both with a 2. Take 3 beans out of Bag 3 and label each with a 3. Continue this pattern with Bags 4 to 10. Put these 55 beans on the tray of the scale.
If all 55 weighed 10 grams, the scale would register 550 grams. But since one or more of the beans weighs 1.1 grams, the scale will register more than 550. Subtract 550 from the number on the scale. Your answer will tell you the number of the bag with the heavier beans.

 

[Cheesetian]

That my friend, would be the obvious answer to the question but i'm afraid it ain't correct because technically that IS more than one reading because as you remove the bags, the number changes. A drop in the number is as good as a different measurement. It has to be 0 on the scale, up to whatever number the beans weigh, then back down to 0 after you've removed ALL the beans. Simple. Nice try though, Younglin.

 

[Younglin]

Read again.

 

[Cheesetian]

You got the gist of it. It's simple actually. Just read off the decimal place. If all the beans weighed 1g, there would be 55g on the reading. Let's say the 1.1g beans were from the 7th bag, the reading would be 55.7g.

 

[Younglin]

Exactly.