Question

Marcy played the piano for 45 mins she stopped playing at 4:15 pm at what time did she start playing the piano

Answer 1

we know that
1 hour----------> 60 min

step 1
convert hours to minutes
4:15---------> 4 hour +15 minutes------> 4*60+15-----> 255 minutes

step 2
subtract 45 minutes
255-45--------> 210 minutes

step 3
convert to hour
1 hour----------> 60 min
x-----------------> 210 min
X=210/60---------> X=3.5 hour
3.5 hour
that means
3 hour+0.5 hour
and 0.5 hour is-----------> 0.5*60----> 30 minutes
therefore
3.5 hour-------> 3 hour +30 minutes-------->3:30 pm

the answer is
3:30 pm