Respuesta :

Okay so...
There are 21 groups of 3.
21 x 3 = 63.
63 people are in the room.

Answer: 63 because 21 times 3 = 63

Step-by-step explanation:

There are 63, it can't be 7 because why would there be 7 students in 21 groups, so 21 times 3 equals 63