Step-by-step explanation:
Let 'x' be the number of paint colors Maddie can buy.
She buys 4 paintbrushes that cost $3 each. This means that she already spent 4x3=$12 in paintbrushes. This amount plus the amount of money she'll spend in the paint colors must be at most $40:
![12+6x\le40](https://img.qammunity.org/2023/formulas/mathematics/high-school/ggy3rocinh7r9vrxl69nu1fyfsvjqtxluj.png)
Solving for x:
![\begin{gathered} 12-12+6x\le40-12 \\ 6x\le28 \\ x\le(28)/(6) \\ x\le4.\bar{6} \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/eqcfxn04cmplltq25ii8c2qj0dyissi5ov.png)
Since x must be a whole number (is the amount of paint colors) and it has to be less than 4.666... then Maddie can afford 4 paint colors
Answer:
Maddie can afford 4 paint colors