Çözüldü Two-Variable Equations (8th Grade)

From Syracuse University:

At a recent Syracuse University basketball game there were a total of 17,500 tickets sold. The price of an adult ticket is $30, and the price of a child ticket is $15. If the total amount collected from ticket sales was $450,000, how many adults and children bought tickets for the game?

a. Identify and assign symbols to the variables in this problem. [2 points]
b. Write the two symbolic rules relating the variables. [2 points]
c. Solve the problem to determine how many adult and child tickets were sold. [2 points]
https://researchguides.library.syr.edu/ld.php?content_id=41348006
(Page 6, Question 10)

Solution:
a.
The number of adults: A
The number of children: C

b.
A + C = 17500....(I)
30·A + 15·C = 450000 ⇒ 2A + C = 30000....(II)

c.
Subtracting the equation (I) from (II) side by side yields A = 12500....(III)
Substituting the value at (III) for its place in the eqquation (I); 12500 + C = 17500 ⇒ C = 5000.