Give your answer in the 24-hour clock form, for example, 15:00.

A new bookstore opened on 15 July at 12:00. Another bookstore opened next door 25 hours later. What is the date and time when the second store opened?

16 July

First bookstore: 12:00 15 July

Second bookstore: 12:00 + 25 h = 1 day 13:00

So the answer is 13:00 16 July.