Well, to do this, you have to remove everything that is attached to n, leaving only n. So first of all, you have to divide both sides by 3/8. You have to do this because 3/8 is the farthest thing attached to n, you have to start from the farthest. You divide because the relationship between 3/8 and n which is in parenthesis is multiplication, and the opposite of multiplication is division. Anyway, that will be;
3/8(n+10) =6 ÷ 3/8
3/8
The two 3/8 will cancel each other. And like i said before, when dividing with a fraction, you have to turn the fraction upside down. So;
(n+10)=6 x 8/3
n+10=48/3
48 divided by 3 is 16. So;
n+10=16
Now to find n, you have to take away what is attached, and that is 10. The relationship between 10 and n is addition, the opposite of addition is subtraction, so you have to subtract 10 from both sides. So;
n+10-10=16-10
+10-10 is 0. And 16-10 is 6. So;
n=6. YOUR ANSWER IS C. Hope i helped, have a nice day. Let me know if you have any more problems.