Evaluate $\lfloor 11.1 \rfloor + 2 \cdot \lfloor 0.5 \cdot 11.1 \rfloor .$
I know that $\lfloor x \rfloor$ means the greatest integer that is less than or equal to x, so $\lfloor 11.1 \rfloor = 11$. I also know that multiplying by 0.5 is the same as dividing by 2, so $\lfloor 0.5 \cdot 11.1 \rfloor = \lfloor 5.55 \rfloor = 5$. Now I just need to substitute these values into the expression and simplify: $\lfloor 11.1 \rfloor + 2 \cdot \lfloor 0.5 \cdot 11.1 \rfloor = 11 + 2 \cdot 5 = 11 + 10 = 21$. 