Pick the odd one out

Pakistan
May 23, 2007 1:04am CST
If you have 17 identical color and identical shape balls. There one ball which slightly heavier than others. In how many least attempts you can definitely find the odd one out........
1 response
krayzee
@krayzee (1160)
• Romania
27 May 07
I think the answer is 4. First you compare the weight of 8 of the balls with the weight of another 8. If they're equal means the 17th is the heavier. Else you take the 8 balls from the heavier side and split it in two groups of four and compare them. Then you take the heavier 4, split it into two groups of two and compare them, and then you take the two heavier and compare them against each other.
miyounus
@miyounus (35)
• Pakistan
28 May 07
The method u are using is something near binary search. i.e. break in two and than search. What about if we break it in three as 6,6,5 or 5,5,7 initially and than by dividing it in two groups, so you can get it in 3 attempts at max.
krayzee
@krayzee (1160)
• Romania
28 May 07
You're right :)