The volleyball team at West View High School is comparing T-shirt companies where they can purchase their practice shirts. The two companies, Shirt Box and Just Tees, are represented by this system of equations where x is the number of T-shirts and y is the total cost of the T-shirts.
y = 10.5x
y = 7.5x + 30
How many T-shirts would the volleyball team need to purchase from each company for the total cost to be equal?