Answer:
Tickets were sold in advance are 60 and the tickets were sold at the door are 40.
Explanation:
Given:
Tickets for a high school dance.
Cost $1.00 each of purchased in advance of the dance.
Cost $1.50 each if bought at the door.
100 tickets were sold and $120 was collected.
Now, to find the tickets that were sold in advance and sold at the door.
Let the number of tickets sold in advance be
.
And the number of tickets sold at the door be
.
So, the total number of tickets sold:
![x+y=100.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rgtwc8xajrvnu6kx3ps6887rwcqp8hyy7q.png)
......(1)
Now, the total amount collected:
![1.00x+1.50y=120.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ozmgkp4vi15jmn09j3m2ixiftfkgecxge9.png)
Putting the equation (1) in the place of
we get:
![1x+1.5(100-x)=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zwal7s8d63z0wm5v3um8okp3ae336nad4x.png)
![1x+150-1.5x=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ojgpnup74sv45t9m7kaf5z85f1o7r56bjo.png)
![150-0.5x=120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9c4973qcy8gsbdmx97zo2j56dfyst78w8y.png)
Adding both sides by
we get:
![150=120+0.5x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/s8nibqmntymabiy2s8w5s10ik7k68igvdb.png)
Subtracting both sides by 120 we get:
![30=0.5x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7p9on33dtfx6wglasa5zp73iet0i8nntb6.png)
Dividing 0.5 by both sides we get:
![60=x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/emazctwirwmklw5g819qgwm9h15d390efu.png)
Thus, the number of tickets sold in advance = 60.
Putting the value of
in equation (1) we get:
![y=100-60](https://img.qammunity.org/2020/formulas/mathematics/middle-school/p9c1pni7bybcjqunbkcv80ia2b136eahwj.png)
![y=40.](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zowm4mpexrrx90oatuctvpmnt5vnygci7t.png)
So, the number of tickets sold at the door = 40.
Therefore, tickets were sold in advance are 60 and tickets were sold at the door are 40.