Answer:
adults tickets=1384
kids:616 tickets
1384-616= 768 tickets
Step-by-step explanation:
let x be adult tickets and y kids
x+y=2000 ⇒x=2000-y
20x+12y=35072 solve by substitute for x=2000-y
20(2000-y)+12y=35072
40000-20y+12y=35072
-8y=35072-40000
-8y=-4928
y=-4928/-8
y=616
x=2000-616
x=1384 tickets
check:
20(1384)+12(616)=35072 ( correct)