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Principles of counting .pptx
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- 2. There are somebasic counting techniques which will be useful in determining the number through different ways of arranging or selecting objects. The basic counting principles are Addition principle and Multiplication principle.
- 3. ● ADDITION PRINCIPLE: Ifthere are two selections such that they can be done independently in m ways and n ways respectively, then either of the two selections can be done in (m + n) ways.
- 4. For example: If youare going to a hotel to have food and the hotel offers different food items as
- 6. Solution: ● For tiffin,we can choose one among 7 items in 7 ways ● For meals, we can choose one among 9 items in 9 ways.
- 7. Since two selectionscan be done independently,we use addition principle.Therefore, there are 16 (7 tiffin items + 9 meals items) different ways by which we can choose any one food.
- 8. ● Multiplication principle Ifa selection can be performed in m ways, following which another selection can be performed in n ways, and both the selections are dependent on each other then, the two selections together can be performed in exactly (m × n) different ways.
- 9. For example: Praveen bought3 shirts, 2 jeans and 3 pairs of shoes for his birthday.In how many different ways can Praveen wear a dress on his Birthday?
- 11. Solution: He can wearin the following ways
- 13. Since two selectionsare dependent on each other,we use multiplication principles.Therefore, Praveen can wear his dress in 18 (3×2×3) different possible ways on his birthday.
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