Ask Experts Questions for FREE Help !
Ask
    niceanne's Avatar
    niceanne Posts: 1, Reputation: 1
    New Member
     
    #1

    Mar 25, 2010, 05:03 PM
    Do my homework too
    You are considering buying 9 silver coins that look alike, but you have been told that one of the coins is a lightweight counterfeit. What is the least number of weighing on a balance scale that you can use to be certain that you have found the counterfeit coin?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
     
    #2

    Mar 25, 2010, 07:34 PM

    I know how to do the weighing, but rusty on the math.

    Weigh 8(a) and 1(b)
    If weight of a/8 <> b then b is the bad coin

    Split 8 into two piles of 4(c) and 4(d)
    If weight of c/4 <> b then pile c contains the bad coin
    If weight d/4 <> b then d contains the bad coin

    Take the bad coin pile and divide in two piles of 2
    Do the same test.

    Then you'll have a pile of 2
    Weigh each coin and compare to b
    Clough's Avatar
    Clough Posts: 26,677, Reputation: 1649
    Uber Member
     
    #3

    Mar 25, 2010, 07:47 PM
    Hi, niceanne!

    I'm not sure what you mean by "do my homework too". Would you mind explaining that?

    Thanks!

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Homework language homework [ 1 Answers ]

You see well I have this homeworkassighmentthat isdo first thing in the morning so all I ask is that you write down some words in azorean langugauge! Words: Pencil Sharpener Paper Crayon Pen Binder

Homework [ 3 Answers ]

Why does a business want to keep separate accounts for recording sales of service and sales of goods?

More homework [ 4 Answers ]

Several years ago, Castles in the Sand, Inc. issued bonds at face value at a yield to maturity of 7 percent. Now, with 8 years left until the maturity of the bonds, the company has run into hard times and the yield to maturity on the bonds has increased to 15 percent. What has happened to the price...


View more questions Search