Mr. Chavez's third-graders go to gym class at 11:15. Students rotate through three activities for 8 minute each. Lunch begins at 12:00. How many minutes are left from the end of the gym activities until lunch begins?
21 minutes is the answer because there's 45 minutes between 11: 15 and 12:00 and the 3 activities for eight minutes (8 x 3 = 24) so 45 - 24 = 21 minutes