Dara spends $16 on tubes of paint and disposable brushes for an art project. Each tube of paint costs $3, and each disposable brush costs $.50. Kara purchases twice as many brushes as tubes of paint. Find the number of brushes and the number of tubes of paint that she purchases. Use the equations below to find your answers. Show your work.
x = tubes of paint
y= disposable brushes
x + .5y = 16
y = 2x