Autos arrive at a toll plaza located at the entrance to a bridge at a rate of

Question:

Autos arrive at a toll plaza located at the entrance to a bridge at a rate of 50 per minute during the 5:00-to-6:00 P.M. hour. If an auto has just arrived,
a. What is the probability that the next auto will arrive within 3 seconds (0.05 minute)?
b. What is the probability that the next auto will arrive within 1 second (0.0167 minute)?
c. What are your answers to (a) and (b) if the rate of arrival of autos is 60 per minute?
d. What are your answers to (a) and (b) if the rate of arrival of autos is 30 per minute?