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 amongcoins.nine

Can you determine the procedure?