Solve the Problem Using Matrices $19.69 \%$ Copper to Make Jewelry $15 \%$

Solve the problem using matrices.
-Anne and Nancy use a metal alloy that is $19.69 \%$ copper to make jewelry. How many ounces of an alloy that is $15 \%$ copper must be mixed with an alloy that is $22 \%$ copper to form 100 ounces of the desired alloy?

A) $72 \mathrm { oz }$
B) $67 \mathrm { oz }$
C) $35 \mathrm { oz }$
D) $33 \mathrm { oz }$