Answer:
12.5 or 12 1/2 (may be wrong)
Explanation:
First I set up a formula to solve how many ounces of salt there were out of 30,
x/30=20/100, I crossed multiplied and got 5/30, next, I set up the same formula for how many ounces of salt there were out of 25, x/25=30/100, I got 7.5, the last thing I did was add them both together leading me to the answer 12.5 or 12 1/2. Hope this helps! Please say if I am wrong.