Solve the problem using matrices.
-Anne and Nancy use a metal alloy that is $21 \%$ copper to make jewelry. How many ounces of an alloy that is $14 \%$ copper must be mixed with an alloy that is $24 \%$ copper to form 100 ounces of the desired alloy?
A) $30 \mathrm { oz }$
B) $70 \mathrm { oz }$
C) $75 \mathrm { oz }$
D) $32 \mathrm { oz }$

Question

Quizplus · Accepted Answer

To solve this, let $x$ be the amount of 14% copper alloy and $y$ be the amount of 24% copper alloy. We have two equations: $x + y = 100$ (for the total amount of alloy) and $0.14x + 0.24y = 0.21 \times 100$ (for the amount of copper). Solving these equations simultaneously gives $x = 30$ and $y = 70$.

Solve the Problem Using Matrices 21%21 \%21% Copper to Make Jewelry 14%14 \%14%

Solve the Problem Using Matrices $21 \%$ Copper to Make Jewelry $14 \%$