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Category: Permutation and Combination

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…

In-how-many-ways-can-you-go-up-a-staircase-with-20-steps-if-you-take-one-two-or-three-steps-at-a-time-

Question Number 166770 by mr W last updated on 27/Feb/22 $${In}\:{how}\:{many}\:{ways}\:{can}\:{you}\:{go}\:{up}\:{a}\: \\ $$$${staircase}\:{with}\:\mathrm{20}\:{steps}\:{if}\:{you}\:{take}\: \\ $$$${one},\:{two}\:{or}\:{three}\:{steps}\:{at}\:{a}\:{time}? \\ $$ Commented by MJS_new last updated on 27/Feb/22 $$\mathrm{is}\:\mathrm{it}\:\mathrm{121415}?…

A-panel-of-3-women-and-4-men-is-to-be-formed-from-8-women-and-7-men-Find-the-number-of-ways-which-the-panel-can-be-formed-if-it-must-contain-at-least-2-women-

Question Number 35640 by NECx last updated on 21/May/18 $${A}\:{panel}\:{of}\:\mathrm{3}\:{women}\:{and}\:\mathrm{4}\:{men}\:{is} \\ $$$${to}\:{be}\:{formed}\:{from}\:\mathrm{8}\:{women}\:{and} \\ $$$$\mathrm{7}\:{men}.{Find}\:{the}\:{number}\:{of}\:{ways} \\ $$$${which}\:{the}\:{panel}\:{can}\:{be}\:{formed}\:{if} \\ $$$${it}\:{must}\:{contain}\:{at}\:{least}\:\mathrm{2}\:{women}. \\ $$ Answered by tanmay.chaudhury50@gmail.com last updated…

Three-boys-two-girls-and-a-puppy-sit-at-a-round-table-In-how-many-ways-can-they-be-arranged-if-the-puppy-is-to-be-seated-i-between-the-two-girls-ii-between-any-two-boys-

Question Number 35639 by NECx last updated on 21/May/18 $${Three}\:{boys},{two}\:{girls}\:{and}\:{a}\:{puppy} \\ $$$${sit}\:{at}\:{a}\:{round}\:{table}.{In}\:{how}\:{many} \\ $$$${ways}\:{can}\:{they}\:{be}\:{arranged}\:{if}\:{the} \\ $$$${puppy}\:{is}\:{to}\:{be}\:{seated} \\ $$$$\left.{i}\right){between}\:{the}\:{two}\:{girls} \\ $$$$\left.{ii}\right){between}\:{any}\:{two}\:{boys} \\ $$ Commented by NECx…

A-woman-sent-8-letters-to-her-friends-The-letters-are-kept-in-the-addressed-envelopes-at-random-The-probability-that-4-friends-receive-correct-letters-and-4-letters-go-to-wrong-destination-is-

Question Number 100971 by john santu last updated on 29/Jun/20 $$\mathrm{A}\:\mathrm{woman}\:\mathrm{sent}\:\mathrm{8}\:\mathrm{letters}\:\mathrm{to}\:\mathrm{her}\: \\ $$$$\mathrm{friends}.\:\mathrm{The}\:\mathrm{letters}\:\mathrm{are}\:\mathrm{kept}\:\mathrm{in}\:\mathrm{the} \\ $$$$\mathrm{addressed}\:\mathrm{envelopes}\:\mathrm{at}\:\mathrm{random}.\: \\ $$$$\mathrm{The}\:\mathrm{probability}\:\mathrm{that}\:\mathrm{4}\:\mathrm{friends}\: \\ $$$$\mathrm{receive}\:\mathrm{correct}\:\mathrm{letters}\:\mathrm{and}\:\mathrm{4}\:\mathrm{letters}\: \\ $$$$\mathrm{go}\:\mathrm{to}\:\mathrm{wrong}\:\mathrm{destination},\:\mathrm{is}\:\_\_\_\: \\ $$ Answered by…