Question

There are 8 balls looking alike, seven of which have equal weight and one is slightly heavier. The weighing balance is of unlimited capacity. Using this balance, the minimum number of weightings required to identify the heavier ball is:
1. 1
2. 2
3. 3
4. 4

Answer 1

Correct Answer - Option 3 : 3

Given: 

There are 8 balls looking alike, seven of which have equal weight and one is slightly heavier.

Calculation:

Step 1: Take 4 balls and 4 balls then weigh balance (take out 4 balls whose have maximum weight)

Then for that 4 balls again divide into 

Step 2: From the heavy weight, take 2 balls and 2 balls then weigh balance (take out 2 balls whose have maximum weight)

Then for that 2 balls again divide into 

Step 3: From the heavy weight, take1 bag and 1 bag then weigh balance(so in the last anyone out of these two will heavier ball)

∴The minimum number weightings required to identify the heavier ball is 3.