ruplun wrote:There are 100 cards numbered from 1 to 100.If three cards are selected at random and with replacement , what is the probability that the sum of the 3 numbers on the cards so selected will be odd?
a. 1/4
b. 3/8
c. 1/2
d. 5/8
e. 3/4
Given 3 integers:
Ways to yield an even sum:
even + even + even
odd + odd + even, in any order
Ways to yield an odd sum:
odd + odd + odd
even + even + odd, in any order
Since 1/2 the integers from 1 to 100 are even and 1/2 are odd:
Number of ways to get an even sum = Number of ways to get an odd sum.
Thus, P(odd sum) = 1/2.
The correct answer is
C.
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