This is one of the time related questions tested in most of the 11+ maths exams. Lot of students struggle to answers this as it is a difficult one. However, with a simple trick, this question can be answered.
To this we need to split the question into multiple parts such as 09:34 to 10:00, 10:00 to 13:00, and 13:00 to 13:21.
Total minutes between 09:34 to 10:00 is 26 minutes.
Total hours between 10:00 to 13:00 is three hours.
Total minutes between 13:00 to 13:21 is 21 minutes.
Hence, in total 3 hours and 47 minutes.