B3. Mama bought a curtain rail, 1 m long, and 2 m² of fabric for curtains for the living room. She paid 19000 SIT for everything. At home, she realized that it would be best if she also had a curtain rail and curtains in the dining room. She returned to the store and paid 35500 SIT for a 1.5 m long curtain rail and 4 m² of fabric. How much does 1 m of curtain rail and 1 m² of fabric cost?
B3. If we denote the price of $1 \mathrm{~m}$ of the curtain rail by $x$, and the price of $1 \mathrm{~m}^{2}$ of the fabric by $y$, we can write the equations from the problem statement as: $x+2 y=19000$ and $1.5 x+4 y=35500$. This system of two linear equations with two unknowns can be solved, for example, by the substitution method or the method of opposite coefficients. Solution using the substitution method: From the first equation, we express $x=19000-2 y$. We then substitute this into the second equation: $1.5 \cdot(19000-2 y)+4 y=35500$, which simplifies to $28500-3 y+4 y=35500$ or $y=7000$. Finally, we have $x=19000-2 y=5000$.

Solution using the method of opposite coefficients: We multiply the first equation by (-2) and add it to the second, resulting in $-0.5 x=-2500$ or $x=5000$. We then calculate $y=7000$.

Scoring: Total: 5 points

Choosing the unknowns and setting up the equations, e.g., $x+2 y=19000$ and $1.5 x+4 y=35500 \ldots 2 \mathbf{t}$ Calculated unknowns: $x=5000$ SIT, $y=7000$ SIT .................................. 2 t

Written answer, e.g., $1 \mathrm{~m}^{2}$ of fabric costs 7000 SIT, $1 \mathrm{~m}$ of the curtain rail costs 5000 SIT. . 1 t