# What Is The Most Efficient

Logic Level 2

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.

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