If it has an emergency locator, what is the probability that it will be discovered? Okay so here's the question > Seventy percent of the light aircraft that disappear while in flight in a certain country are subsequently discovered. Of the aircraft that are discovered, 60% have an emergency locator, whereas 90% of the aircraft not discovered do not have such a locator. Suppose that a light aircraft has disappeared. If it has an emergency locator, what is the probability that it will be discovered? Anndd here's **my** answer ![answer]( The answer to this question was, however, given as 93%. I don't understand how they got that answer and I was pretty confident in my solution. Can someone either tell me the answer given in the text is incorrect or what's wrong with my solution? Thanks so much!

Intuitively, you can think of $P(E \mid D)$ in the numerator as "given that you are already inside the $70 \%$ that has been discovered, what is the probability that inside that $70 \% $ it does have an emergency locator?" so you don't take $.7$ into account in the calculation, you only take $.6$.

You can also use the formula $$P(D \mid E) = \frac {P( D \cap E)}{P(E)}= \frac {(.7)(.6)}{(.7)(.6)+(.3)(.1)}$$