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?
weigh three balls against another three balls. if both weigh the same , then just weighing the remain two (one against one) will show the lighter ball. if the sets of three do not weigh equal, then weigh any two balls in the lighter set, one against the other . the balance will show if the lighter one is on the balance,if not the remaining one is the lighter one.
8= (3 + 3 ) + 2
(the numbers in the brackets are balls on either side of the balance)
weigh three balls against another three balls. if both weigh the same , then just weighing the remain two (one against one) will show the lighter ball. if the sets of three do not weigh equal, then weigh any two balls in the lighter set, one against the other . the balance will show if the lighter one is on the balance,if not the remaining one is the lighter one.
ReplyDelete8= (3 + 3 ) + 2
(the numbers in the brackets are balls on either side of the balance)
if both are equal, then
2= (1 + 1) done.
else, from the lighter set of 3
3= (1 + 1) + 1 done.