Probability of Transportation Usage

In a certain city, there are two types of public transportation: buses and trams. A random survey of 1000 people revealed the following:

• 60% use buses.
• 45% use trams.
• 20% use both buses and trams.

What is the probability that a randomly selected person uses either buses or trams?

Let A be the event that a person uses buses, and B be the event that a person uses trams. You are tasked with finding the probability of the union of these two events, represented as $P(A ext{ or } B)$. Recall the formula for the probability of the union of two events: $$P(A ext{ or } B) = P(A) + P(B) - P(A ext{ and } B).$$