How do you solve the puzzle on floor 6 in the tower?

006 Light Weight
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Varies: Weigh 3 vs 3 on round 1. If equal, remove masses and check which of the
remaining goes up. If not equal, discard lower scale masses. Weigh any 2
of the remaining 3 to find the odd, light one.

Or, to put it another way:

Puzzle: 006
Title: Light Weight
Location: Manor Road
Character: Marco
Type: Scale
Solution: First weigh 2 groups of three. If they were balanced, weigh the
remaining two against each other. If not, take the lighter group and
weigh 2 of the 3 against each other. If equal weight, take the third

Thanks and please take a moment to give this solution a rating of fixya.
one. If not, choose the lighter one.