11. How many strikes will a clock make in a day if it strikes the whole number of hours and also marks the midpoint of each hour with one strike?
11. $(1+2+3+\ldots+12) \cdot 2+24=13 \cdot 6 \cdot 2+24=180$.

Translating the above text into English, while preserving the original text's line breaks and format:

11. $(1+2+3+\ldots+12) \cdot 2+24=13 \cdot 6 \cdot 2+24=180$.