Latest Microsoft Aptitude Question SOLUTION: Suppose you had 8 billiard balls, and one of them was slightly heavier, but the only way to tell was by putting it on a scale against another. What's the fewest number of times you

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Suppose you had 8 billiard balls, and one of them was slightly heavier, but the only way to tell was by putting it on a scale against another. What's the fewest number of times you'd have to use the scale to find the heavier ball?

Asked In Microsoft Naveen (13 years ago)

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sayantan chaudhury  (13 years ago)

ANS IS : 2

:- step 1 : take any 3 vs 3
case 0 : they are equally weighted.
case 1 : they are of unequal weight.

for case 0: step 2 : compare remaining two to get the ans.
case 1: step 2 : compare any two from the heavier side.

now 3 case may arise
case 0:any one of the two is heavy
case 1:both r of equal wight so the the ball not weighted is heavier.

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shamarb  (13 years ago)

2 times,
first keep two balls aside,
measure 3 and 3 balls.
condition1: if it is balanced then the heavy ball is in the two which were kept aside
condition2: if any one part is heavey, then the heavy ball is among these 3.
if condition 1 is met,scale the two balls which were kept aside, we'll get heavy ball.
if second condition is met, then take the 3 balls, and keep one ball aside and scale the other two...

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Ankit  (12 years ago)

2 times
scale any 3 ball with the 3 balls
1- balence
2- unbelence
if 1 then heavy ball is one of the two ball which not scale
if 2 then scale any two ball from heavier 3 ball
know the heavy ball

Is this solution Helpfull? Yes (4) | No (1)  

Sandeep Maan  (12 years ago)

First of all make 2 groups of 4 balls.Remove lighter group after checking through. After that make 2 groups of 2 balls,repeat previous process.At 3rd time we will find the heavier ball.

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B.Rajashekar  (13 years ago)

3 Times scale should be used
first time 4 one side and other the same then it shows heavier weight side then remove other
second time take two of heavier side and keep them other side
then we will find heavier side.
third time Take heavier side two balls and keep them one on each side then we will find heavier wieght ball

Is this solution Helpfull? Yes (1) | No (8)  

Shiv Kumar  (12 years ago)

3 times.
1) first time 4 balls on each side, heavier side will down. Take those four balls and do the second time balance
2) two on each side, heavier one will go down. take those two balls and balnce those two for third time by placing one on each side.
3) This is which ball goes down is the heavier one

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Ambika Prasad Tiwari  (12 years ago)

divide the ball in groups of four...
comparison 1:compare one against other
one group will come out to be heavier
comparison 2:divide the heavier group into balls of two
compare one group with another
one group will come out to be heavier
comparison 3:now among the group compare one ball with another
we will now come to know who is the heaviest ball
so it will take 3 comparisons to find the heaviest ball..

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Pradeep Yadav  (12 years ago)

it depends on what are we using to scale their weight.... if we are using "Taraju" then it answer will be 3 times.

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