Answer:
45 adult tickets sold
Explanation:
let c be each child ticket sold and a be the adult tickets sold
6a+3.50c=340 represents the cost while a+c=65 is the tickets sold
if you solve by elimination you have to multiply the second equation by -3.50 to get a new equation of -3.50a-3.50c=-227.50 then you subtract both equations and get 2.5a=112.5 the you divide both sides by 2.5 to get a=45
which means there were 45 adult tickets sold