How to figure percentage?? HELP

My co workers and I are starting a summer challenge tomorrow and we want to use percentage instead of pounds to pick a weekly winner

Do anyone know how to figure that out?

Help!!

 ARGH! Math!!! 

 Let's see if I can do this right.

Example: you start out weighing 150 pounds and you lose 18.

You divide 18 by the 150 and you get 12. You've lost 12% of your body weight.

 you would divide pounds lost by total pounds X 100 to get a percent

so    if you are say    250 and lost 5 pounds

5/250=.02 X 100  = 2            it would be a 2% loss

The second answer seems right, from the sense I got on biggest looser and what I remember from math class. The first one is too high. That's great the contest in percent of weight loss, makes it more fair. Some people start out bigger than others. Have fun with it, hope it's a motivator.

Just make an Excell spreadsheet and have it do it for you.