Frank started practicing his trumpet at 4:30 pm and finished at 6:00 pm. How long did he practice?
A. 2 hours and 30 minutes
B. 2 hours
C. 30 minutes
D. 1 hour and 30 min
4:30 pm can be also expressed as 16:30, while 6:00 pm can be expressed as 18:00. The difference between them is 01:30, therefore the answer is D, 1 hour and 30 minutes.
