Jump to content
BrainDen.com - Brain Teasers

Recommended Posts

  • 4 weeks later...
This sequence won't work:

1, 2, 4, 8, 16, 32, 64, 128, 258, 512.

Here is why. If the 10th bag only is full of fakes you'll get an extra weigh amount of 51.2g.

And, if bags 2-9 are fake then you'll get (25.8+12.8+6.4+3.2+1.6+.8+.4+.2) 51.2g and then you won't be able to tell which situation you are in.

The total extra sum has to be distinct for any combo of fake bags.

the sequence will work

cuz the sum of both 2-9 (what u mentioned, dunno y u didnt say 1-9) and 1-9 is not 51.2. its 51 and 51.1. check it. do u know the formula for sum of a GP?

Link to post
Share on other sites
  • 1 year later...

To Garrek99: We are working with a scale here, not a balance. It may be used once. If you choose to weigh all ten bags, these bags must be placed on the scale, and there is no reason why they cannot be placed on the scale one at a time. As they are placed on the scale, notice how much the weight reading increases. Of course, this scale could have a blank lcd readout that will display its one and only reading to you when you hit the "ready" button. Then this would not work. Then it's back to the powers of two.

Link to post
Share on other sites
Guest
This topic is now closed to further replies.
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...