For this case, we propose a system of two equations with two unknowns.
Let:
x: Represents the number of children's tickets
y: Represents the number of adult tickets
![5.20x + 8.60y = 931.20\\x + y = 132](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xe7lf32gwtinr9f30m6d4e95o7czaogb9i.png)
So, we clear x from the second equation:
x = 132-y
We replace in the first one.
![5.20 (132-y) + 8.60y = 931.20\\686.4-5.20y + 8.60y = 931.20\\-5.20y + 8.60y = 931.20-686.4\\3.4y = 244.8\\y = \frac {244.8} {3.4}\\y = 72](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5ghbipkhzg154qy57y388xb27b0mkwqwpu.png)
72 adult tickets were sold.
![x = 132-y\\x = 132-72\\x = 60](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z3i55zg9ntt5er47fg9eqgkuau5sfwkoi0.png)
60 tickets for children were sold
Answer:
60 tickets for children
72 adult tickets