Solution:
Let us denote by x the number of child tickets sold and by y the number of adult tickets sold. According to the problem, we have that 137 tickets were sold, then we get the following equation:
Equation 1:
![x+y\text{ = 137}](https://img.qammunity.org/2023/formulas/mathematics/college/g802ggilpdnj95cyx4fpscfgldat08afch.png)
On the other hand, according to the problem, child admission is $5.80 and adult admission is $9.70 and the total sales were S1094.90.
Thus, we get the following equation:
Equation 2:
![5.80x\text{ + 9.70y = }1094.90](https://img.qammunity.org/2023/formulas/mathematics/college/c06nqffxxq8s0cgfo553h0h53k1t3pcl6h.png)
Thus, we get the following system of linear equations:
Equation 1:
![x+y\text{ = 137}](https://img.qammunity.org/2023/formulas/mathematics/college/g802ggilpdnj95cyx4fpscfgldat08afch.png)
Equation 2:
![5.80x\text{ + 9.70y = }1094.90](https://img.qammunity.org/2023/formulas/mathematics/college/c06nqffxxq8s0cgfo553h0h53k1t3pcl6h.png)
Now, solving for x, the equation 1, we get:
Equation 3:
![x=\text{ 137-y}](https://img.qammunity.org/2023/formulas/mathematics/college/thb1h25r7cjlyh2n7ky86sa8znhl7yvrt6.png)
replacing this into equation 2, we obtain:
![5.80(137-y)\text{ + 9.70y = }1094.90](https://img.qammunity.org/2023/formulas/mathematics/college/51jjrsxz63o1ekkbdwk4plft56182i8s69.png)
now, applying the distributive property, we get:
![794.6-5.80y\text{ + 9.70y = }1094.90](https://img.qammunity.org/2023/formulas/mathematics/college/kxuevj9hqpgxnrmmd84wypbthbgd3y0ggm.png)
this is equivalent to:
![-5.80y\text{ + 9.70y = }1094.90-794.6](https://img.qammunity.org/2023/formulas/mathematics/college/acopza9ek45hmaaesxms5zgtpj6sxce0a3.png)
this is equivalent to:
![3.90y=300.3](https://img.qammunity.org/2023/formulas/mathematics/college/64qa0tylbmutl9d5mhlfo27avy6g6rclgh.png)
solving for y, we get:
![y=(300.3)/(3.90)=77](https://img.qammunity.org/2023/formulas/mathematics/college/ursdp20ueyzitne0vcx146ejlauddkrjra.png)
Now, replacing this data into equation 3, we obtain:
![x=\text{ 137-y}=137-77=60](https://img.qammunity.org/2023/formulas/mathematics/college/tap8raxckbd8jk80vlhnm0f75ijck11v0h.png)
So that, we can conclude that the correct answer is:
the number of child tickets sold = x = 60
the number of adult tickets sold = y = 77