Kara spent $16 on paint and brushes. paint costs $3 per tube and a brush costs $.50. kara bought twice as many brushes as tubes of paint. Find the number of brushes and the number of tubes of paint that kara bought.

Let’s define our variables.
Let t stand for tubes of paint and b stand for brushes.

Next, make some equations with the information provided.

3t+0.50b=16
b=2t

Next use substitution. Plug 2p in for b in the first equation.

3t+0.5(2t)=16

3t+t=16

4t=16

Divide by 4 on both sides, and t=4.

Now, we have to find the number of brushes.

Plug 4 in for t in the 2nd equation.

b=2t
b=2(4)
b=8

4 tubes of paint, 8 brushes