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Seth and Anna go to a cafe to buy a drink each. They can choose from Coke, Sprite and L&P.
It is equally likely as to which drink they buy, Find the probability that both of them buy a coke
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There are three drinks for each to choose from, and the probability is 1/3
for every drink to be selected by Seth and/or by Anna, independently.
Therefore, the probability that both of them will select coke independently is
P = = . <<<---=== ANSWER
Solved.
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You can solve the problem by another way, considering the set of possible outcomes.
It consists of 9 pairs (drink_Seth,drink_Anna), so you have 9 possible outcomes
with equal probabilities. It leads to the same answer.