5 adult tickets and 15 children tickets was purchased by Mr. Ramirez
Since we do not know the number of individual ticket types, we represent them with variables
Let the number of adult tickets be a and the number of children tickets sold be c
The sum of both ticket types is 20
Thus, mathematically;
The cost per adult ticket is $15; so the cost of 'a' adult tickets will be 15 * a = $15a
The cost per children ticket is $10; so the cost of 'c' children tickets will be 10 * c = $10c
The sum of both is $225
Thus, we have it that;
So we have two equations to solve simultaneously
From the first equation, we can have a as the subject of the equation
This will give;
Substitute this in the second equation;
Recall from above;