4017. The number of trucks traveling along the highway on which the gas station stands is one of the cars passing along the same highway as 2: 3. It is known that, on average, one out of thirty trucks and two out of fifty cars drive up to a gas station to refuel. What is the probability that:
a) a truck drove up to the gas station and it will refuel;
b) a passenger car drove up to the gas station and it will refuel;
c) the car which approached the gas station will be refueled.

Detailed solution. Decorated in Microsoft Word 2003 (Quest decided to use the formula editor)