You have 8 balls. One of them is defective and weighs less
than others. You have a balance to measure balls against
each other. In 2 weighings how do you find the defective one?
Answer Posted / balbir singh
Firstly we take 6 balls, placing 3 on each pan of the
balance & check which pan goes up(1st weighing). If no
change it means the balls don't contain the defective
one,therefore the other two contain the defective
ball,which can be found out easily(2nd weighing).
Now if one of the pan goes up,it means it contains the
defective ball(out of 3 balls).We select these 3 & unload
the pans. Now we keep any of the 2 balls(from the selected
balls)on either side of the balance & weigh(2nd weighing).
One of these two will be the defective one and if not the
3rd one leftover is.
Is This Answer Correct ? | 67 Yes | 6 No |
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