If the minute turned 90 degrees by the time recess ended, the time recess ended is 12.15.
What time did recess end?
A clock has is in the shape of a circle. Thus, the sum of angles in a circle is 360 degrees. Also, there are 60 minutes in an hour.
Total minutes moved = (degree moved / total degree in a circle) x 60minutes
(90 /360) x 60 = 15 minutes
Time recess ended = 12 : 00 + 15 minutes = 12 : 15