At a certain gas stations, 50% of the customers use regular unleaded gas (A1), 30% use extra unleaded gas (A2), and 20% use premium unleaded gas (A3) of the customers using regular gas only, 30% fill their tanks (event B). 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 (A union B)?