Question 1089084

A piggy bank contains 36 coins that consists of dimes and quarters totaling $5.85. How many quarters are in the piggy bank? In your final answer, include all necessary calculations.
The problem I am having is putting this question in an system of linear equation and in substitution form and graphing it
I first tried x = .36 + y = 5.85 but the calculations dies not come out what  am I doing wrong?
<pre>Let the number of dimes be D and quarters, Q
Then we get the system: {{{system(D + Q = 36, .1D + .25Q = 5.85)}}} 
You solve the system for Q: the number of quarters, since that's what's being sought.
OR
You don't have to have a system. You can solve with just one variable, as follows:
Let the number of quarters be Q
Then number of dimes = 36 - Q
We then get the following equation: {{{matrix(1,3, .25Q + .1(36 - Q), "=", 5.85)}}}
You solve the system for Q: the number of quarters, since that's what's being sought.