Answer: 4.8 hours
Step-by-step explanation:
Given
The castle must be guarded 24 hr by 5 knights
If duty is split equally among them
No of hours spent by each knight on duty
[tex]\Rightarrow n=\dfrac{24}{5}=4.8\ \text{hours}[/tex]
Therefore, each guard must serve a duty of 4.8 hours