a) The total number of vehicles is 2450, and the number of vehicles that didn't use a toll pass is 1566, so the probability is:

b) If it's given that the vehicle is a truck, the number of trucks is 951, and the number of trucks that didn't use a toll pass is 610, so the probability is:
-4 and 0 are the x-intercepts
0, sqrt(9), 16.00, -4, -2, and -5 are all whole numbers because they all simplify to numbers without decimals