Answer: There are 4 tubes of paint she purchased.
Step-by-step explanation:
Since we have given that
Amount spend on tubes of paint and brushes for an art project = $16
Cost of each tube of paint = $3
Cost of each brush = $0.50
Let the price of tube of paint be 'x'.
Let the price of brush be '2x'.
So, According to question, it becomes,

Hence, there are 4 tubes of paint she purchased.