70% of light aircraft that disappear while flying in a certain country are subsequently discovered. Of the aircraft that are discovered, 60% have an emergancy locator, whereas 90% of the aircraft not discovered do not have such a locator. Suppose a light aircraft has dissappeared.
a) If it has a locator, what is the probability it will not be discovered
b) If it does not have an emergency locator, what is the probability it will be discovered?