Suppose you have 63 nickels, dimes, and quarters combined that total $8.20. Write a system of equations.

Question

I am to write a system of equations and then create a matrix for the problem.

Answer 1

You only have two equations and 3 variables.

 

Usually this question would have a relationship between nickels and dimes, dimes and quarters, or nickels and quarters for the 3rd equation.

 

The only two you have:

 

N + D + Q = 63

.05(N) + .1(D) + .25(Q) = 8.20  =>  Multiply by 20 to get rid of the decimals => 1N + 2D + 5Q = 164

 

Without one more you can't solve the equation.