Many utility companies promote energy conservation by offering discount rates to consumers who keep their energy usage below certain established subsidy standards. a recent epa report notes that 70% of the island residents of puerto rico hae reduced their electricity usage sufficiently to qualify for discounted rates. if five residential subscribers are randomly selected from san juan, puerto rico, find the probability of each of the following events.

a. all five qualify for the favorable rate
b. at least four qualify for the favorable rates