जॉइन Examsbookउत्तर : 1. "28"
Find the number of ways in which 21 balls can be distributed among 3 persons such that each person does not receive less than 5 balls.5
प्र: Find the number of ways in which 21 balls can be distributed among 3 persons such that each person does not receive less than 5 balls.
- 128true
- 214false
- 321false
- 47false
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उत्तर : 1. "28"
व्याख्या :
Answer: A) 28 Explanation: Let x, y, z be the number of balls received by the three persons, then x≥5, y≥5, z≥5 and x+y+z=21 Let u≥0, v≥0, w≥0 then ∴ x + y + z =21 ⇒ u + 5 + v + 5 + w + 5 = 21 ⇒ u + v + w = 6 ∴Total number of solutions = C3-16+3-1=C28=28