In a promotion, Joana bought blouses for $\mathrm{R} \$ 15.00$ each and pants for $\mathrm{R} \$ 17.00$ each, spending a total of $\mathrm{R} \$ 143.00$. How many blouses and pants did Joana buy?
Let $b$ and $c$ be the number of blouses and pants bought, respectively. Therefore, we have $15 b + 17 c = 143$, where $b$ and $c$ are positive integers. Note that $b < 10$ and $c < 9$, because both $15 \times 10$ and $17 \times 9$ are greater than 143. From this point, we present two possible solutions.

Solution 1: We have $15 b = 143 - 17 c$, so $143 - 17 c$ is a multiple of 15, meaning that $143 - 17 c$ ends in 0 or 5. This means that $17 c$ ends in 3 or 8. Therefore, $c = 9$ or $c = 4$. Since $c < 9$, the only solution is $c = 4$, and therefore,

$$
b = \frac{143 - 17 \times 4}{15} = 5
$$

Thus, Joana bought five blouses and four pants.

Solution 2: We have

$$
b = \frac{143 - 17 c}{15} = 9 - c + \frac{8 - 2 c}{15}
$$

Note that $c$ is a positive integer, so $8 - 2 c$ must be a multiple of 15. If $8 - 2 c \geq 15$, $c$ results in a negative number, so $8 - 2 c = 0$, that is, $c = 4$. From this, we obtain that $b = 5$. Thus, Joana bought five blouses and four pants.