Question

a total of 78 seats for a concert are sold, producing a total revenue of $483. if seats cost either $2.50 or $10.50, how many $2.50 seats and how many $10.50 seats were sold?

Answer 1

x -> seats $2.50
y -> seats $10.50

x + y = 78
2.50*x + 10.50*y = 483

now just solve this linear system