At a certain gas station, 40% of the customers use regular unleaded gas (A1), 35% use midgrade unleaded gas (A2), and 25% use premium gas (A3). Of those customers using regular gas, only 30% fill their tank (event B). Of those customers using extra gas, 60% fill their tank, whereas of those using premium gas, 50% fill their tank.
(a) What is the probability that the next customer will requestplus gas and fill their tank ?
(b) What is the probability that the next customer fills thetank ?
Imagine 100 customers
40 want reg 30% fill (12 customers)
35 want midgrade 60% fill (21 customers)
25 want premium 50% fill (12.5 customers)
plus gas and fill would be 12.5 % ( but you mixed descriptions in your q if PLUS gas is EXTRA gas , the answer would be 21 %)
next customer wants fill? (12 + 21 + 12.5) = 45.5 %