   Find the lighter ball..

75 views

There are 8 balls. All of them have the same weight, except one that is lighter. How can you identify the lighter one in 3 steps, using a balance? posted Jan 24, 2014

It can be done in two steps ONLY !!

make two groups of 3 balls each and one group of 2 balls (i.e 3+3+2=8)

Step 1: Measure group of 3,3 on the weighing machine.

case 1. If two groups are equal then the defected(less weight) ball is in group of 2 balls.
Step 2: Measure those two balls, you will get the defected one. [2 steps only]
case 2. If one of the group of 3 balls is less heavy then that particular group contains the defected ball. divide this group into 3 groups of 1 ball each (i.e 1+1+1=3).
Step 2: weight any two balls ...If one of those two is less heavy then that is your answer.if both are equal then the third ball is answer. [2 steps only] answer Jan 24, 2014

Similar Puzzles
+1 vote

You are an expert on paranormal activity and have been hired to locate a spirit haunting an old resort hotel. Strong signs indicate that the spirit lies behind one of four doors. The inscriptions on each door read as follows:

Door A: It's behind B or C
Door B: It's behind A or D
Door C: It's in here
Door D: It's not in here

Your psychic powers have told you three of the inscriptions are false, and one is true. Behind which door will you find the spirit? 