Can excell calculate information for me and if so, how?

I have a product that currently is used at 3% application...

I would like to take this product and add another product to it at various
rates. 5%, 4%, 3%, 2%, and 1%. The final product would still be used at 3%
application. The two products vary greatly in cost. I need to calculate the
final costs into this. Is there a program in excell that I can input these
numbers and percentages into?