A person collects coins (nickels, dimes, and quarters) in a jar. At the end of the year they emptied the jar and found that there were 110 coins. The value of all the coins was $11.20. If there were twice as many dimes as quarters, how many of each type of coin were there?
a) Define the variables needed to solve the problem
b) Set up a system of equations modeling the facts.
c) Find the solution by solving the system of equations in b) using rref on your calculator (show the original matrix and the row-reduced matrix).