Answer:
64 adult tickets were sold
Step-by-step explanation:
Let a = adult tickets sold
c = child tickets sold
a+c = 90 since there were 90 tickets sold
12a+7c = 950 since the amount of money collect is 950
c = 90-a
Substitute this into the second equation
12a +7( 90-a) = 950
Distribute
12a + 630-7a = 950
Combine like terms
5a +630 = 950
Subtract 630 from each side
5a = 950-630
5a = 320
Divide by 5
5a/5 = 320/5
a =64
64 adult tickets were sold
