After having done this on paper:
[tex] \frac{n}{3} + 8 = 16 [/tex]
We want to isolate the variable, and the first step is to subtract the 8.
[tex] \frac{n}{3} = 8[/tex]
Since the n is being multiplied by 3, and that = 8, we can multiply both sides by 3.
n = 24
Let me know if this helped you understand better.
Also, you can check this by substituting in 24 for n.