Permutation and Combination

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Three children,each accompanied by a guardian,seek admission in a school.The principal wants to interview all the 6 persons one after the other,subject to the condition that no child is interviewed before its guardian.In how many ways can this be done?

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Soumyadeep Basu ·2013-10-17 00:15:39

Total no. of ways without any restrictions is 6!=720.
For every child-guardian pair, there are two possibilities: either the child comes first or the guardian comes first. Now, discarding the cases where the child comes first for the three pairs, the total no. of ways is 7202.2.2=90.

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Manish Shankar good work :)
Upvote·0· Reply ·2013-10-17 22:08:52
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Basic Integral Calculus Operators Symbols Matrix Cases

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∫ ∫ ∫ ∫ ∫ ∬ ∬ ∬ ∬ ∬ ∭ ∭ ∭ ∭ ∭ ⨌ ⨌ ⨌ ⨌ ⨌

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° ∂ ∞ α β γ δ θ λ μ ν ξ π ρ σ φ ω ε ƒ κ τ υ Γ Δ Λ Σ Π Ω

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Permutation and Combination

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