How many weighings of a balance scale are needed to find a lighter counterfeit coin among four coins? Describe an algorithm to find the lighter coin using this number of weighings.
Can some one please help me with this ???
Hello, bhuvan!
How many weighings of a balance scale are needed
to find a lighter counterfeit coin among four coins? . . . . Two
Describe an algorithm to find the lighter coin using this number of weighings.
Weighing #1: Weigh two coins against the other two.
. . The pan that is higher contains the lighter coin.
Weighing #2: Weigh the coins from the higher pan against each other.
. . The coin in the higher pan is the counterfeit.
With two weighings, the lighter coin can be found from among nine coins.
Can you determine the procedure?