Hours in a day

Your book, Maths Mela (Chapter 12), shows a doctor's whole day on a big clock ring. The doctor wakes up at 6 o'clock in the morning. She cooks and gets ready from 6 to 8: that is 2 hours. She travels to the hospital from 8 to 9 (1 hour) and stays at the hospital from 9 in the morning to 4 in the afternoon.

How long is 9 to 4? Count the hours: 9 to 10, 10 to 11, 11 to 12, 12 to 1, 1 to 2, 2 to 3, 3 to 4. That is 7 hours. Then she travels home from 4 to 5 (1 hour) and rests from 5 to 6 (1 hour). From 6 in the morning to 6 in the evening: 2 + 1 + 7 + 1 + 1 = 12 hours.

In the evening she cooks from 6 to 7 (1 hour), spends time with her children from 7 to 8 (1 hour), and has dinner and watches TV from 8 to 10 (2 hours). She sleeps from 10 at night to 6 the next morning: 10 to 12 is 2 hours and 12 to 6 is 6 hours, so 8 hours. From 6 in the evening to 6 the next morning: 1 + 1 + 2 + 8 = 12 hours.

So a whole day, from 6 in the morning to 6 the next morning, is 12 + 12 = 24 hours. A day has 24 hours.