Solution: Math Puzzle: Find the Heavy Ball
Solution: Find the Heavy Ball Math Puzzle
Leo can do it in two weighings. Here’s how:
Let’s pursue outcome A first. If three balls balance against another three, then the heavy one must be among the remaining three that are not on the scale. So, for the next step:
Now let’s go back to Step 1 and pursue outcome B. In this case, take the three balls that weigh in as heavier and proceed to Step 2 using them.
In either case, it takes just two weighings to isolate the one heavy ball out of nine. Leo can now proceed up the tower to drop the two balls. Of course, he is very careful about safety and will make sure there is no one below before he releases the balls.