Question 234485
a+c=520 or a=520-c
10a+3c=3450
10(520-c)+3c=3450
5200-10c+3c=3450
-7c=3450-5200
-7c=-1750
c=1750/7
c=250 number of children tickets sold.
a+250=520
a=520-250
a=270 adult tickets sold.
Proof:
10*270+3*250=3450
2700+750=3450
3450=3450