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tbhauer
for this problem, it is easier to determine the probability the problem is NOT solved, and subtract from one to solve for the probability that the problem IS solved.
P(not solved) = (1- \(\frac{2}{7}\)) * (1- \(\frac{4}{7}\)) * (1- \(\frac{4}{9}\))
= \(\frac{5}{7}\) * \(\frac{3}{7}\) * \(\frac{5}{9}\)
= \(\frac{75}{441}\)
= \(\frac{25}{147}\)
P(solved) = 1 - \(\frac{25}{147}\)
= \(\frac{122}{147}\)
ANS = A


Hi. This is a good take on the problem. But I have a question: Why don't we tackle the problem directly, without determining the probability of NOT solving?
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