Question 25799
LEt the cjilderns tickets be x
 let the adults tickets be y
Now x+y=100 Solve for y
y=100-x
Childern tickets = $3
Adults = $6
3x+6y=390 (SUBSITUTE)
3x+6(100-x)=390
3x+600-6x=390
-3x=-210
x=70
y=100-70
y=30


Hence, about 70 childern tickets were sold, and about 30 adults tickets were sold.
Paul.