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A box contains 100 balls, numbered from 1 to 100

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A box contains 100 balls, numbered from 1 to 100. If three balls are selected at random and with replacement from the box, what is the probability that the sum of the three numbers on the balls selected from the box will be odd?
A. 1/4
B. 3/8
C. 1/2
D. 5/8
E. 3/4
Official Answer

1 Answer

Manshul Arora
There are two sets that would make odd result - e+o+e in this the order would matter.
So 1)eeo 2)eoe 3) oee probablity would be 1/8 each.
Noe another pair is ooo in this ordder wont matter. So its 1/8 again. Total 1/8+1/8+1/8+1/8 that is 1/2
Anither approach however would be.. There are 50 odd and 50 even no. Total 4 combi possible
Evn evn evn,
Od od od,
Even odd odd,
Evn evn odd,
Two of these sets would make even no. And another two would make odd.
So simply the probablity is 1/2
answered Jun 18, 2015 by Beginner (1 point)
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