Three defective bulbs got mixed up with seven good ones. ...
Three defective bulbs got mixed up with seven good ones. If two bulbs are selected at random, what is the probability that both are good?
\(\frac{3}{7}\)
\(\frac{21}{50}\)
\(\frac{7}{15}\)
\(\frac{49}{100}\)
Correct answer is C
\(P(\text{both bulbs are good}) = \frac{7}{10} \times \frac{6}{9}\)
= \(\frac{7}{15}\)