Answer:
The system is of equations is:
![\left\{ \begin{array}{ll} 10g+15r=725 & \quad \\ g+r=60 & \quad \end{array} \right.](https://img.qammunity.org/2022/formulas/mathematics/college/6a3lhbt793le422xj1hnt46rdthbhcuhs4.png)
Where g is the amount of general tickets and r is the amount of reserve tickets.
35 general tickets and 25 reserve tickets were sold.
Explanation:
Let general tickets be represented by g and reserved tickets be represented by r.
Each general ticket sells for $10 each and reserved tickets $15 each. Dave collected a total of $725. Thus:
![10g+15r=725](https://img.qammunity.org/2022/formulas/mathematics/college/fpfps3i8ev9b071tblce010qypicpx7qya.png)
And a total of 60 tickets were sold. Hence:
![g+r=60](https://img.qammunity.org/2022/formulas/mathematics/college/wt4d8ik7d3fnam09yzg43g2wvj8rkfvru5.png)
Our system of equations is:
![\left\{ \begin{array}{ll} 10g+15r=725 & \quad \\ g+r=60 & \quad \end{array} \right.](https://img.qammunity.org/2022/formulas/mathematics/college/6a3lhbt793le422xj1hnt46rdthbhcuhs4.png)
We can solve by substitution. First, divide both sides of the first equation by 5:
![2g+3r=145](https://img.qammunity.org/2022/formulas/mathematics/college/bx9v5gtt3uvszjekbrh4xlxbhpicg9haf0.png)
Next, we can subtract a variable (r in this case) from the second equation:
![g=60-r](https://img.qammunity.org/2022/formulas/mathematics/college/i2br739dskcz5h539qoeoawdjo1a8zc6sj.png)
Substitute:
![2(60-r)+3r=145](https://img.qammunity.org/2022/formulas/mathematics/college/pvuqj39qnktboncitb231cjcrxw7hsnszk.png)
Distribute:
![120-2r+3r=145](https://img.qammunity.org/2022/formulas/mathematics/college/ef3s8w19uv6wr708dojgl7rwarcarirdez.png)
Simplify:
![120+r=145](https://img.qammunity.org/2022/formulas/mathematics/college/lwemz3roz9e1wqr7w3dxk0edpuvulj5ao0.png)
Subtract:
![r=25](https://img.qammunity.org/2022/formulas/mathematics/college/zbkjlws4ciic9t62677an7jntb35oeh9sb.png)
Using the previous equation:
![g=60-r](https://img.qammunity.org/2022/formulas/mathematics/college/i2br739dskcz5h539qoeoawdjo1a8zc6sj.png)
Substitute and evaluate:
![g=60-(25)=35](https://img.qammunity.org/2022/formulas/mathematics/college/ccp8m1o8d0a7h0ywkjguxtrn44k71ytrt3.png)
So, 35 general tickets and 25 reserve tickets were sold.