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 i of autos is 60 per minute?
d. What are your answers to (a) and (b) if the rate of i of autos is 30 per minute?