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1410

Q: 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.

  • 1
    28
  • 2
    14
  • 3
    21
  • 4
    7
  • Show Answer
  • Workspace

Answer : 1. "28"
Explanation :

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

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