vidhya16 wrote:The probability that a visitor at the mall buys a pack of candy is 30%. If three visitors come to the mall today, what is the probability that exactly two visitors will buy a pack of candy?
* 0.343
* 0.147
* 0.189
* 0.063
* 0.027
P(exactly n) = P(one way) * total possible ways.
P(one way):
One way to get a good outcome is for the first visitor not to buy a pack of candy while the second and third visitors do.
P(1st visitor doesn't buy candy) = 7/10.
P(2nd visitor buys candy) = 3/10.
P(3rd visitor buys candy) = 3/10.
To determine the probability that all of these events happen together, we multiply the fractions:
7/10 * 3/10 * 3/10 = .063.
Total possible ways:
Since any of the 3 visitors could be the one not to buy candy, the result above must be multiplied by 3:
3 * .063 = .189.
The correct answer is
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