Answer:
21
Step-by-step explanation:
To find the total atoms.
Multiply 3 *2 and you will get 6
Then multiply 3 * 5 and you will get 15.
You do this because there is 3 as a coefficient and is before the chemical compound. Furthermore, that means the same thing as a parenthesis.
Last of all, add 15 + 6 and you will get 21.
Therefore, there are a total of 21 atoms.