Ahmed is regularly late to lessons. He has an average lateness of 7 minutes. There are 20 lessons a week and 38 weeks a year. Work out how many hours of learning he has missed over the course of a year.

Because he has 20 lessons a week, and is late 7 times a lesson, we know that he misses 20*7 minutes a week.

Because there are 38 weeks a year, we multiply the unit rate by 38:

38*140 = 5320

Because we're looking for hours, not minutes, we divide by 60:

5320/60

532/6

8 (4/6)

8 2/3 hours