You have 4 weights weighing 2,3,5 and 7 pounds. The problem is none of them are marked. What is the fewest number of weighings you need using a balance scale figure out which weights are which?
(In reply to
a computerized start by Charlie)
With the useless lines deleted, it's:
a 2 2 2 2 2 2 3 3 3 3 3 3 5 5 5 5 5 5 7 7 7 7 7 7
b 3 3 5 5 7 7 2 2 5 5 7 7 2 2 3 3 7 7 2 2 3 3 5 5
c 5 7 3 7 3 5 5 7 2 7 2 5 3 7 2 7 2 3 3 5 2 5 2 3
d 7 5 7 3 5 3 7 5 7 2 5 2 7 3 7 2 3 2 5 3 5 2 3 2
ab v d \ - - / / / \ - / / / / - / / / / / / / / / / / 18 4 2
ab v c - \ / - / / - \ / / / / / - / / / / / / / / / / 18 4 2
ab v cd \ \ \ \ / / \ \ \ \ / / \ \ \ \ / / / / / / / / 12 0 12
ac v d - / \ / - / / / \ / - / / / - / / / / / / / / / 18 4 2
a v d \ \ \ \ \ \ \ \ \ / \ / \ / \ / / / / / / / / / 12 0 12
ad v c / - / \ / - / / / \ / - / / / - / / / / / / / / 18 4 2
a v c \ \ \ \ \ \ \ \ / \ / \ / \ / \ / / / / / / / / 12 0 12
a v cd \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ - - \ \ - - / / 2 4 18
ac v b / / - / \ - / / - / \ / / / / / - / / / / / / / 18 4 2
ac v bd \ / \ / \ \ \ / \ / \ \ \ / \ / \ \ / / / / / / 12 0 12
ad v b / / / - - \ / / / - / \ / / / / / - / / / / / / 18 4 2
a v b \ \ \ \ \ \ / / \ \ \ \ / / / / \ \ / / / / / / 12 0 12
a v bd \ \ \ \ \ \ \ \ \ \ \ \ \ - \ - \ \ - / \ / \ - 2 4 18
ad v bc / \ / \ \ \ / \ / \ \ \ / \ / \ \ \ / / / / / / 12 0 12
a v bc \ \ \ \ \ \ \ \ \ \ \ \ - \ - \ \ \ / - / \ - \ 2 4 18
bc v d / / / / / / - / - / / / \ / \ / / / - / - / / / 18 4 2
b v d \ \ \ / / / \ \ \ / / / \ \ \ / / / \ \ \ / / / 12 0 12
bd v c / / / / / / / - / - / / / \ / \ / / / - / - / / 18 4 2
b v c \ \ / \ / / \ \ / \ / / \ \ / \ / / \ \ / \ / / 12 0 12
b v cd \ \ \ \ \ \ \ \ \ \ - - \ \ \ \ / / \ \ \ \ - - 2 4 18
c v d \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / 12 0 12
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Posted by Charlie
on 2004-07-25 12:06:55 |