11. There is a clock, which is 25 seconds slow every hour. On March 21 this year, it showed the correct time at noon. When will this clock show the correct time again? 

What is the date and time when this clock will next show the correct time?
11.【Solution】When this clock is 12 hours slow, it will indicate the correct time again. Being 12 hours slow requires
$$
\begin{array}{l}
\frac{60 \times 60 \times 12}{25}=12 \times 12 \times 12 \text { (hours) } \\
\text { which is equivalent to: } \frac{12 \times 12 \times 12}{24}=72 \text { (days) }
\end{array}
$$

Note that March has 31 days, April has 30 days, and May has 31 days. By June 1st at noon, it is exactly 72 days.

Answer: The next time it indicates the correct time is June 1st at noon 12:00.