A serving tray made of brass weighs 21 ounches...Percentage problem I don't understand...?

Question

Could you please help me and possibly explain how to get the answer. What is the answer?

A serving tray made of brass weighs 21 ounces. This brass is an alloy of 70 percent copper and 30 percent tin. What is the weight of copper in the tray?

I did....

21/100 X 70

Answer 1

You're right. 21/100 x 70 = 14.7.

That's how to do it, "per cent" just means hundredths. So the copper is 70 hundredths of the total weight.