[superprismatic]

Suppose you see before you 10 identical-looking

blocks. No two of these blocks weigh the same.

Your task is to sort the blocks according to

weight using the fewest number of weighings.

For any given weighing, you are free to use any

one of eight scales labeled S2, S3, S4, S5, S6,

S7, S8, and S9. Scale SN (where N is between 2

and 9 inclusive) works by taking precisely N

blocks, sorting those blocks by weight, and

reporting to you their weight-ordering.

What is the fewest number of weighings needed to

determine the weight-ordering of all 10 blocks?

[Guest]

3

weigh 9 of them

then weigh the 10th and 8 heaviest

if the 10th is the lightest weigh it against the lightest if not you have them in order

[superprismatic]

3

weigh 9 of them

then weigh the 10th and 8 heaviest

if the 10th is the lightest weigh it against the lightest if not you have them in order

No, you're not missing something. Now try A Funky Weighing Puzzle II.