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Category: Permutation and Combination

3-men-and-4-women-are-to-sit-on-a-table-Calculate-the-number-of-possible-sitting-arrangements-if-a-they-sit-in-a-row-such-that-the-men-must-not-sit-next-to-each-other-b-they-

Question Number 167979 by nadovic last updated on 31/Mar/22 $$\mathrm{3}\:\mathrm{men}\:\mathrm{and}\:\mathrm{4}\:\mathrm{women}\:\mathrm{are}\:\mathrm{to}\:\mathrm{sit}\:\mathrm{on}\:\mathrm{a} \\ $$$$\mathrm{table}.\:\mathrm{Calculate}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of} \\ $$$$\mathrm{possible}\:\mathrm{sitting}\:\mathrm{arrangements}\:\mathrm{if} \\ $$$$\:\left({a}\right)\:\mathrm{they}\:\mathrm{sit}\:\mathrm{in}\:\mathrm{a}\:\mathrm{row}\:\mathrm{such}\:\mathrm{that}\:\mathrm{the} \\ $$$$\:\:\:\:\:\:\:\:\:\mathrm{men}\:\mathrm{must}\:\mathrm{not}\:\mathrm{sit}\:\mathrm{next}\:\mathrm{to}\:\mathrm{each} \\ $$$$\:\:\:\:\:\:\:\:\:\mathrm{other}. \\ $$$$\:\left({b}\right)\:\mathrm{they}\:\mathrm{sit}\:\mathrm{in}\:\mathrm{circular}\:\mathrm{pattern}\:\mathrm{and} \\ $$$$\:\:\:\:\:\:\:\:\mathrm{the}\:\mathrm{clockwise}\:\mathrm{and}\:\mathrm{anticlockwise} \\…

Consider-triangle-ABC-If-206-lines-are-drawn-from-A-to-BC-how-many-triangles-are-formed-

Question Number 36398 by NECx last updated on 01/Jun/18 $${Consider}\:{triangle}\:{ABC}.{If}\:\mathrm{206} \\ $$$${lines}\:{are}\:{drawn}\:{from}\:{A}\:{to}\:{BC}\:{how} \\ $$$${many}\:{triangles}\:{are}\:{formed}? \\ $$ Commented by Rasheed.Sindhi last updated on 02/Jun/18 $$\mathrm{207}+\mathrm{206}+…+\mathrm{1}=\frac{\mathrm{207}×\mathrm{208}}{\mathrm{2}}=\mathrm{21528} \\…

There-are-10-identical-mathematics-books-7-identical-physics-books-and-5-identical-chemistry-books-Find-the-number-of-ways-to-compile-the-books-under-the-condition-that-same-books-are-not-mutually-

Question Number 101732 by mr W last updated on 04/Jul/20 $$\mathrm{There}\:\mathrm{are}\:\mathrm{10}\:\mathrm{identical}\:\mathrm{mathematics} \\ $$$$\mathrm{books},\:\mathrm{7}\:\mathrm{identical}\:\mathrm{physics}\:\mathrm{books} \\ $$$$\mathrm{and}\:\mathrm{5}\:\mathrm{identical}\:\mathrm{chemistry}\:\mathrm{books}. \\ $$$$\mathrm{Find}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{ways}\:\mathrm{to}\:\mathrm{compile}\: \\ $$$$\mathrm{the}\:\mathrm{books}\:\mathrm{under}\:\mathrm{the}\:\mathrm{condition}\:\mathrm{that} \\ $$$$\mathrm{same}\:\mathrm{books}\:\mathrm{are}\:\mathrm{not}\:\mathrm{mutually}\:\mathrm{adjacent}. \\ $$ Commented by…

Question-101393

Question Number 101393 by bemath last updated on 02/Jul/20 Answered by 1549442205 last updated on 02/Jul/20 $$\mathrm{Suppose}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{cars}\:\mathrm{manufactured} \\ $$$$\mathrm{in}\:\mathrm{the}\:\mathrm{first}\:\mathrm{yeat}\:\mathrm{be}\:\mathrm{n}\:\mathrm{units}\:.\mathrm{Then}\:\mathrm{in}\:\mathrm{the}\:\mathrm{second}\:\mathrm{year} \\ $$$$\mathrm{is}\:\frac{\mathrm{3n}}{\mathrm{2}}\:\mathrm{and}\:\mathrm{in}\:\mathrm{the}\:\mathrm{third}\:\mathrm{year}\:\mathrm{is}\:\mathrm{2n}\:.\mathrm{Sum}\:\mathrm{of}\:\mathrm{cars} \\ $$$$\mathrm{manufactured}\:\mathrm{in}\:\mathrm{the}\:\mathrm{3\_years}\:\mathrm{period}\:\mathrm{is} \\ $$$$\frac{\mathrm{9}\boldsymbol{\mathrm{n}}}{\mathrm{2}\:}.\boldsymbol{\mathrm{Hence}}\:\boldsymbol{\mathrm{P}}=\frac{\frac{\mathrm{3}\boldsymbol{\mathrm{n}}}{\mathrm{2}}}{\frac{\mathrm{9}\boldsymbol{\mathrm{n}}}{\mathrm{2}}}=\frac{\mathrm{1}}{\mathrm{3}}\Rightarrow\boldsymbol{\mathrm{Choose}}\:\boldsymbol{\mathrm{A}}…

How-many-permutations-of-the-letters-of-the-word-EINSTEIN-are-possible-if-the-EIN-groups-must-not-be-next-to-eachother-

Question Number 166787 by nadovic last updated on 27/Feb/22 $$\mathrm{How}\:\mathrm{many}\:\mathrm{permutations}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{letters}\:\mathrm{of}\:\mathrm{the}\:\mathrm{word}\:\mathrm{EINSTEIN}\:\mathrm{are} \\ $$$$\mathrm{possible}\:\mathrm{if}\:\mathrm{the}\:\mathrm{EIN}\:\mathrm{groups}\:\mathrm{must}\:\mathrm{not} \\ $$$$\mathrm{be}\:\mathrm{next}\:\mathrm{to}\:\mathrm{eachother}? \\ $$ Commented by mr W last updated on…