Answer: The price for the adult tickets is $12 and the price for the child ticket is $5.
Explanation:
Let the price for the adult ticket be x
Let the price for the child ticket be y
According to question, On Friday ,
![4x+7y=83](https://img.qammunity.org/2020/formulas/mathematics/high-school/ecfw4f9qg9my7oz2o6fbci2ep8x91kmudu.png)
and on next day,
![5x+6y=90](https://img.qammunity.org/2020/formulas/mathematics/high-school/1sfpjdn1aj3ycveev8yenfijnybtcsni7s.png)
Now, we will use "Substitution Method" to solve the system of equations :
![5x+6y=90\\\\5x=90-6y\\\\x=(90-6y)/(5)](https://img.qammunity.org/2020/formulas/mathematics/high-school/v529ol1aurivdssq3q6y4xjjcghumx3wom.png)
so, we will put the value of x in the first equation i.e.
![4x+7y=83\\\\4((90-6y)/(5))+7y=83\\\\360-24y+35y=83* 5\\\\35y-24y=415-360\\\\11y=55\\\\y=(55)/(11)\\\\y=5](https://img.qammunity.org/2020/formulas/mathematics/high-school/xzthbskleepyvflw3ibnfsp932pcfmxklg.png)
Now, put the value of y in the equation that is given by
![x=(90-6y)/(5)\\\\x=(90-6* 5)/(5)\\\\x=(90-30)/(5)\\\\x=(60)/(5)\\\\x=\$12](https://img.qammunity.org/2020/formulas/mathematics/high-school/1arotwonr0debs7wp64nbtw9kqj5lwqxxv.png)
Hence, the price for the adult tickets is $12 and the price for the child ticket is $5.