Question 26
Find all the pairs $(x, y)$ of real numbers fulfilling
$$
3 \cdot \left\{ \frac{3x+2}{3} \right\} + 4 \cdot \left\lfloor \frac{4y+3}{4} \right\rfloor = 4 \cdot \left\{ \frac{4y+3}{4} \right\} + 3 \cdot \left\lfloor \frac{3x+2}{3} \right\rfloor = 18.
$$
$$
3 \cdot \left\{ \frac{3x+2}{3} \right\} + 4 \cdot \left\lfloor \frac{4y+3}{4} \right\rfloor = 4 \cdot \left\{ \frac{4y+3}{4} \right\} + 3 \cdot \left\lfloor \frac{3x+2}{3} \right\rfloor = 18.
$$