Answer:

Step-by-step explanation:
Let <em>A</em> be the event that Daniel receives call from SeaWorld.
Probability of event <em>A</em>, <em>P(A)</em> =
Let <em>B</em> be the event that Daniel receives call from Central Park Zoo.
Probability of event <em>B</em>, <em>P(B) </em>= 
Probability that Daniel receives calls from both SeaWorld and Central Park Zoo:

We know that formula:
Probability that Daniel receives call from either SeaWorld or Central Park Zoo but not both:

Hence, required probability is
.