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?
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Answer / b.r>madhududan
CASE 1: First we should take six balls divided equally and
then it is placed on the two pans.three on one and three on
other..
if the two pans are balanced then the defective ball is not
in the six..then we should the two and keep them one ball
on each.
CASE2: Again We should take any of the six balls and
divided equally and then it is placed on the two pans.. if
any of the pan weighs less than the other.. We should take
the three balls seperately..Now from that three we should
take any two and placed one on each.. fi both the pan
balances the ball which is left over is the defective.. if
one ball weighes less than the other,while keeping one on
each,then it is the defective one....
| Is This Answer Correct ? | 129 Yes | 13 No |
divide the balls into three groups. Let group A contains 3
balls group B contains 3 balls and group C contains 2 balls.
FIRST TIME: BALANCE the groups A and B.
case 1:
If they are equal then the defective ball is in group C.
case 2: if they are not equal then take the group of 3
balls which has less weight.
SECOND TIME:
IF the defective ball is in group C, we can easily find the
ball which is less.
if the defective ball is in group of 3 which has less
weight, take 2 balls out of this group and find the weight.
if they are equal, then the left out is defective. if not
we can find easily the ball which weigh less.
so we have the following steps:
A (3) B(3) c(2)
|_____________| |
first time /\ |
unequal equal then c has defective.use
| second time to find out
second time take lessweight group
| Is This Answer Correct ? | 49 Yes | 9 No |
Answer / fahad sheikh
Divide the 8 balls into three groups
G1: 1,2,3
G2: 4,5,6
G3: 7,8
Weight 1: Weight G1 against G2, if G1=G2 then lighter ball
is in G3. If G1<G2, then lighter ball is in G1 otherwise is
in G2
Weight 2: If lighter ball is in G3, then weight 7 and 8 no
ball against eachother and find the lighter one.
If lighter ball is in G1 or G2 then divide the group into
two further groups
G4: 1,2
G5: 3
Now weight ball no 1 and 2 against eachother. if 1==2 then
defective is 3 otherwise ball with lesser weight is the
lighter one.
| Is This Answer Correct ? | 10 Yes | 2 No |
Answer / venki
divide 8 balls into 2 groups..
and take 1 ball from each...
after that weigh 2 groups if they weigh same then weigh the 2 balls. otherwise take the less weigh group and weigh any of 2
if those 2 are same then remaining ball is result .
| Is This Answer Correct ? | 6 Yes | 3 No |
Answer / laxman
divide 8 balls into two halves 4 each
step1: take a set of 4 balls and divide into two sets of two
balls eeach and wight them,if theres diference in
weight defective ball is in this set of 4 ball..else
consider other set of 4 balls(extra step)
step2: consider the set of 2 balls having less weight and
weight them and pick the defective ball
best case 2 steps...worst case 3 steps
| Is This Answer Correct ? | 2 Yes | 9 No |
Answer / dinagaran.a
By Using Divide and Conquer Mechanism easily we can
find the defective one.
| Is This Answer Correct ? | 9 Yes | 33 No |
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