Math
posted by Caleb .
128 is what percent of 640?
3.4 is what percent of 5?
15 is what percent of 120?

Divide 128 by 640 and you get 0.2. More the decimal point two places to the right to get the percent.
120 is 20% of 640.
Now that you see how to figure this type of problem, you can do the other two. If you post your answers, we'll be glad to check them.