From 24 grams to 96 grams ( percent change )

Which equation and solution can be used to solve this problem? thirteen less than a number is sixteen. 13-n=16: add 13 to both sides. the answer is 29. n+13=16: subtract 13 from both sides. the answer is 3. n+16=13 subtract 13 from both sides. the answer is 3. n-13=16: add 13 to both sides. the answer is 29.

I'm being volume of cylinder with 13 in. radius and 30 in height answer choices in pic

For each proportion find the unknown number x 1/5/8=×/15