You spend $20 total on tubes of paint and disposable brushes for an art project. tubes of paint cost $4.00 each and paintbrushes cost $0.50 each. you purchase twice as many brushes as tubes of paint. how many brushes and tubes of paint do you purchase?

Let x be the number of tubes of paint purchased. With this representation, the number of paintbrushes purchased is equal to 2x. The equation that would allow us to relate these variables with the given total amount is,
  
    (4)(x) + (0.50)(2x) = 20

The value of x is equal to 4. Thus, 2x is equal to 8.

brushes = 8
              paint = 4

The answer is part a: use

No i refuse to tell you the answer but the estimate is 10