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?
if worst case is taken , answer has to be 64 ....
say 64 = 32+32
2 tests ach give 1 , 1 ==2
then 16 from 1st and 16 from 2nd ==2
then 8 from 1st and 8 from 2nd ==2
then 4 from 1st and 4 from 2nd ==2
then 2 from 1st and 2 from 2nd ==2
umm i ll think if better way r possible ....
till then my answer is 64

Posted by siddhesh
on 20061017 14:47:51 