At a certain gas station, 40% of the customers use regular unleaded gas, 35% use extra unleaded gas and 25% use premium unleaded gas. Of those customers using regular gas, only 30% fill their tanks. Of those customers using extra gas, 60% fill their tanks, whereas of those using premium, 50% fill their tanks.
a. What is the probability that the next customer will request extra unleaded gas and fill the tank? State the rule used.
b. What is the probability that the next customer fills the tank?
c. If the next customer fills the tank, what is the probability that regular gas is not requested?
I calculated parts a and b, but I just want to ensure part c is correct. Would it be the P(A' l F) where A is the regular unleaded, and F the event of a customer filling the tank? If you could do parts a and b, that would be great to compare with what I've got, but not necessary.