The sophomore class sold a total of 700 adult and student tickets to the school play. Adult tickets sold for $4.50 each and student tickets cost $2.oo each. If they took in a total of $1,200, which system of equations can be used to find x, the number of student tickets sold, and y; the number of adult tickets sold?
A: x+y = 1200
2x+4.5y =700
B: x+y=700
2x+4.5y=1200
C: x+y=1200
x+y = 700