Lesson 3.8: Calendar & Clock Problems

Description:
Calendar and clock questions involve finding days, dates, and angles between hands of a clock.

Calendar Problems:

• Find day of the week for a given date.

• Example: What day was 15th August 1947?

Shortcut:
Use Odd Day method:

• 1 century = 5 odd days.

• 1 normal year = 1 odd day, 1 leap year = 2 odd days.

Clock Problems:

• Find the angle between hour and minute hand.

• Formula:
  $\text{Angle}=|(30\times \text{Hour})-(11/2\times \text{Minutes})|$

Example:
Find angle at 3:15 →
$(30\times 3)-(11/2\times 15)=90-82.5=7.5°$.