Question

Last week christi spent 2 3/4 hours playing piano this week she spent 3 2/4 hours playing the piano how much more time did she play the piano this week

Answer 1

Given that last week christi spent 2 3/4 hours playing piano this week she spent 3 2/4 hours playing the piano, the extra time spent on piano this week will be:
3 2/4-2 3/4
Converting the above into proper fraction we get:
14/4-11/4
=(14-11)/4
=3/4
Thus she spent and extra 3/4 hours=45 minutes this week