A clock is set right at 5 a.m., as shown. It loses 16 minutes in every 24 hours. What will the correct time be when it shows 10 p.m. on the fourth day?

From 5 a.m. on day 1 to 10 p.m. on day 4 the dial runs 3 days 17 h = 89 h. It shows $23\frac{11}{15}$ h for every 24 true hours, so true time $=89\times \frac{24\times 15}{356}=90$ h: 1 h more, i.e. 11:00 p.m. (10:56 p.m. adds 16 min per day only roughly.)