Suppose you have \(9\) identical balls, out of which \(8\) have same mass and \(1\) has a slightly higher mass. Using a common balance, what is the least number of weighings we need to guarantee that we find the odd (massive) one in all cases?
Note: A common balance will tell us if the objects in both pans have the same weight. It does not tell us the weight of either pan. You can weigh multiple balls at the same time.
Excel in math and science
Master concepts by solving fun, challenging problems.
It's hard to learn from lectures and videos
Learn more effectively through short, conceptual quizzes.
Our wiki is made for math and science
Master advanced concepts through explanations,
examples, and problems from the community.
Used and loved by 4 million people
Learn from a vibrant community of students and enthusiasts,
including olympiad champions, researchers, and professionals.
Your answer seems reasonable.
Find out if you're right!