Q:

In a school, the bell is rung once after each half an hour. The school starts at 8:00 a.m. and closes at 1: 30 p.m. The bell is rung 3 times continuously, at the time of beginning, at the time of lunch break at 10:00 and 10:30 a.m. and at the end. How many times is the bell rung every day? 

• 1
  21
• 2
  22
• 3
  19
• 4
  20