Math Weight Question

[Jazcam]

I have not taken a math class in years.

I was watching "The Biggest Loser" and one of the contestants weighted in:
Beginning weight 330#
Present weight: 253#

His percentage of weight loss was 23.3%. How did they figure that out?

 

[Jazcam]

Sorry I posted this in the wrong place :+

 

[jackie7]

(330-253)/330

Subtract the weight loss and divide the result by the beginning weight.
Result id 0.23333, then multiply by 100 to get the percent. The result is 23.33333%