Part a: what you have to do is add up all of the vehicles and you get 150. Then it says "approximate probability of a passenger car..." so you would take the number of passenger cars (which is 112) and put that number over 150. 112/150. you would get 0.746666666667 and round that up and you would get 75% (B)
Part b: you do the same thing but change the passenger car number into light truck number. (which is 18) 18/150 0.12 which is 12% (B)