Answer:
64 people
Explanation:
in the morning, 4 people are called. Those 4 people call 4 more people, which brings it to 16 people called. Those 16 people then each call 4 others, which is 16 x 4. Giving you the answer of 64 people for the evening.
FYI, if the question asked how many people were called in total, you would add the 4 people from the morning, 16 people from the afternoon, and 64 people in the evening to get a total of 84 people called.
Hope this helps!