You have N coins, 2 of which are radioactive. You have a radioactivity
detector which can test any subset of the coins at a time, and return the
number of radioactive coins in the group (i.e. it returns 0, 1 or 2). You have to find the radioactive coins, using not more than 10 tests. What is the largest N for which this is possible?
(In reply to
Puzzle Thoughts by K Sengupta)
Following are the solutions for k <9
k |n
--------
0 | 2
1 | 2
2 | 3
3 | 5
4 | 8
5 | 13
6 | 22
7 | 38
8 | 65
Puzzle Solution
