Answer :
From 4 PM to 6 PM is 2 hours, and it's 15 minutes after 6, so her dance class is 2 hours and 15 minutes long.
The answer is 1 hour and 45 minutes because 4:30-5:30 is one hour than 5:30-6:15 is 45 minutes and then you just add them together and it gives you 1 hour and 45 minutes.