You are incorrect. The correct order of operation is:
terms inside brackets
exponents and roots
multiplication AND division
addition AND subtraction
In the absence of parentheses, multiplication and division are performed left to right.
So it would be:
48/2(9+3)
48/2 * 12 <-— this is now left -> right!
24 * 12
288
See post 401. This is from PurpleMath.com and explains what happens with the parentheses. Using their logic, the correct answer is 2.