You have 8 balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more.
How can you find the ball that is heavier by using a balance and only two weighing?
Answer:-
please leave comments if you have any questions.
How can you find the ball that is heavier by using a balance and only two weighing?
Answer:-
Divide the balls into the following groups: (1,2,3),(4,5,6),(7,8)
Step 1.
Weigh (1,2,3) against (4,5,6)
Two possible outcomes:
The two groups are equally heavy. (Case A)
One of these groups is heavier than the other. (Case B)
Case A
Weigh 7 against 8. Now you have identified the heavier ball in 2 weighing.
Case B
Take the heavier group (assume it to be (1,2,3)), take any two balls and weigh them against each other. Either one of these is heavier else the third ball is.
Step 1.
Weigh (1,2,3) against (4,5,6)
Two possible outcomes:
The two groups are equally heavy. (Case A)
One of these groups is heavier than the other. (Case B)
Case A
Weigh 7 against 8. Now you have identified the heavier ball in 2 weighing.
Case B
Take the heavier group (assume it to be (1,2,3)), take any two balls and weigh them against each other. Either one of these is heavier else the third ball is.
please leave comments if you have any questions.
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