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Category: Permutation and Combination

A-teacher-conducts-a-test-for-five-students-He-provides-the-marking-scheme-and-asked-them-to-exchange-their-scripts-such-that-none-of-them-marks-his-own-script-How-many-ways-can-the-students-carry-o

Question Number 111394 by Aina Samuel Temidayo last updated on 03/Sep/20 $$\mathrm{A}\:\mathrm{teacher}\:\mathrm{conducts}\:\mathrm{a}\:\mathrm{test}\:\mathrm{for}\:\mathrm{five} \\ $$$$\mathrm{students}.\:\mathrm{He}\:\mathrm{provides}\:\mathrm{the}\:\mathrm{marking} \\ $$$$\mathrm{scheme}\:\mathrm{and}\:\mathrm{asked}\:\mathrm{them}\:\mathrm{to}\:\mathrm{exchange} \\ $$$$\mathrm{their}\:\mathrm{scripts}\:\mathrm{such}\:\mathrm{that}\:\mathrm{none}\:\mathrm{of}\:\mathrm{them} \\ $$$$\mathrm{marks}\:\mathrm{his}\:\mathrm{own}\:\mathrm{script}.\:\mathrm{How}\:\mathrm{many}\:\mathrm{ways} \\ $$$$\mathrm{can}\:\mathrm{the}\:\mathrm{students}\:\mathrm{carry}\:\mathrm{out}\:\mathrm{the} \\ $$$$\mathrm{marking}? \\…

What-is-the-sum-of-the-coefficients-in-the-expansion-of-2015v-2015u-1-2015-

Question Number 111393 by Aina Samuel Temidayo last updated on 03/Sep/20 $$\mathrm{What}\:\mathrm{is}\:\mathrm{the}\:\mathrm{sum}\:\mathrm{of}\:\mathrm{the}\:\mathrm{coefficients}\:\mathrm{in}\:\mathrm{the} \\ $$$$\mathrm{expansion}\:\mathrm{of}\:\left(\mathrm{2015v}−\mathrm{2015u}+\mathrm{1}\right)^{\mathrm{2015}} ? \\ $$ Commented by mr W last updated on 03/Sep/20…

In-a-tennis-tournament-n-women-and-2n-men-played-Each-player-played-exactly-one-match-with-every-other-player-If-there-are-no-ties-and-the-number-of-the-matches-won-by-women-to-the-number-of-matches

Question Number 111275 by Aina Samuel Temidayo last updated on 03/Sep/20 $$\mathrm{In}\:\mathrm{a}\:\mathrm{tennis}\:\mathrm{tournament}\:\mathrm{n}\:\mathrm{women}\:\mathrm{and} \\ $$$$\mathrm{2n}\:\mathrm{men}\:\mathrm{played}.\:\mathrm{Each}\:\mathrm{player}\:\mathrm{played} \\ $$$$\mathrm{exactly}\:\mathrm{one}\:\mathrm{match}\:\mathrm{with}\:\mathrm{every}\:\mathrm{other} \\ $$$$\mathrm{player}.\:\mathrm{If}\:\mathrm{there}\:\mathrm{are}\:\mathrm{no}\:\mathrm{ties}\:\mathrm{and}\:\mathrm{the} \\ $$$$\mathrm{number}\:\mathrm{of}\:\mathrm{the}\:\mathrm{matches}\:\mathrm{won}\:\mathrm{by}\:\mathrm{women} \\ $$$$\mathrm{to}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{matches}\:\mathrm{won}\:\mathrm{by}\:\mathrm{men} \\ $$$$\mathrm{is}\:\mathrm{7}:\mathrm{5},\:\mathrm{find}\:\mathrm{n}. \\…

Tricolours-flags-each-flag-having-three-different-strips-of-non-overlapping-colours-are-to-be-designed-using-white-blue-red-yellow-and-black-strips-How-many-of-the-flags-have-blue-colour-

Question Number 111272 by Aina Samuel Temidayo last updated on 03/Sep/20 $$\mathrm{Tricolours}\:\mathrm{flags}\left(\mathrm{each}\:\mathrm{flag}\:\mathrm{having}\right. \\ $$$$\mathrm{three}\:\mathrm{different}\:\mathrm{strips}\:\mathrm{of} \\ $$$$\left.\mathrm{non}−\mathrm{overlapping}\:\mathrm{colours}\right)\:\mathrm{are}\:\mathrm{to}\:\mathrm{be} \\ $$$$\mathrm{designed}\:\mathrm{using}\:\mathrm{white},\mathrm{blue},\mathrm{red},\mathrm{yellow} \\ $$$$\mathrm{and}\:\mathrm{black}\:\mathrm{strips}.\:\mathrm{How}\:\mathrm{many}\:\mathrm{of}\:\mathrm{the} \\ $$$$\mathrm{flags}\:\mathrm{have}\:\mathrm{blue}\:\mathrm{colour}? \\ $$ Answered…

How-many-ways-can-the-letters-in-the-word-MATHEMATICS-be-rearranged-such-that-the-word-formed-neither-starts-nor-ends-with-a-vowel-and-any-four-consecutive-letters-must-contain-at-least-a-vowel-

Question Number 110729 by mr W last updated on 30/Aug/20 $$\mathrm{How}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can}\:\mathrm{the}\:\mathrm{letters}\:\mathrm{in} \\ $$$$\mathrm{the}\:\mathrm{word}\:\boldsymbol{\mathrm{MATHEMATICS}} \\ $$$$\mathrm{be}\:\mathrm{rearranged}\:\mathrm{such}\:\mathrm{that}\:\mathrm{the}\:\mathrm{word} \\ $$$$\mathrm{formed}\:\mathrm{neither}\:\mathrm{starts}\:\mathrm{nor}\:\mathrm{ends}\:\mathrm{with}\:\mathrm{a}\: \\ $$$$\mathrm{vowel},\:\mathrm{and}\:\mathrm{any}\:\mathrm{four}\:\mathrm{consecutive}\: \\ $$$$\mathrm{letters}\:\mathrm{must}\:\mathrm{contain}\:\mathrm{at}\:\mathrm{least}\:\mathrm{a}\:\mathrm{vowel}? \\ $$ Answered by…

A-blind-man-is-to-place-6-letters-into-6-pigeon-holes-how-many-ways-can-atleast-5-letters-be-wrongly-placed-Note-that-only-one-letter-must-be-in-a-pigeon-hole-

Question Number 110524 by Aina Samuel Temidayo last updated on 29/Aug/20 $$\mathrm{A}\:\mathrm{blind}\:\mathrm{man}\:\mathrm{is}\:\mathrm{to}\:\mathrm{place}\:\mathrm{6}\:\mathrm{letters}\:\mathrm{into}\:\mathrm{6} \\ $$$$\mathrm{pigeon}\:\mathrm{holes},\:\mathrm{how}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can} \\ $$$$\mathrm{atleast}\:\mathrm{5}\:\mathrm{letters}\:\mathrm{be}\:\mathrm{wrongly}\:\mathrm{placed}? \\ $$$$\left(\mathrm{Note}\:\mathrm{that}\:\mathrm{only}\:\mathrm{one}\:\mathrm{letter}\:\mathrm{must}\:\mathrm{be}\:\mathrm{in}\:\mathrm{a}\right. \\ $$$$\left.\mathrm{pigeon}\:\mathrm{hole}\right). \\ $$ Answered by mr…

In-the-square-PQRS-K-is-the-midpoint-of-PQ-L-is-the-midpoint-of-QR-M-is-the-midpoint-RS-N-is-the-midpoint-of-SP-and-O-is-the-midpoint-of-KM-A-line-segment-is-drawn-from-each-pair-of-points-from-

Question Number 110523 by Aina Samuel Temidayo last updated on 29/Aug/20 $$ \\ $$$$\mathrm{In}\:\mathrm{the}\:\mathrm{square}\:\mathrm{PQRS},\:\mathrm{K}\:\mathrm{is}\:\mathrm{the} \\ $$$$\mathrm{midpoint}\:\mathrm{of}\:\mathrm{PQ},\:\mathrm{L}\:\mathrm{is}\:\mathrm{the}\:\mathrm{midpoint}\:\mathrm{of} \\ $$$$\mathrm{QR},\:\mathrm{M}\:\mathrm{is}\:\mathrm{the}\:\mathrm{midpoint}\:\mathrm{RS},\:\mathrm{N}\:\mathrm{is}\:\mathrm{the} \\ $$$$\mathrm{midpoint}\:\mathrm{of}\:\mathrm{SP}\:\mathrm{and}\:\mathrm{O}\:\mathrm{is}\:\mathrm{the}\:\mathrm{midpoint} \\ $$$$\mathrm{of}\:\mathrm{KM}.\:\mathrm{A}\:\mathrm{line}\:\mathrm{segment}\:\mathrm{is}\:\mathrm{drawn}\:\mathrm{from} \\ $$$$\mathrm{each}\:\mathrm{pair}\:\mathrm{of}\:\mathrm{points}\:\mathrm{from} \\…

How-many-ways-can-the-letters-in-the-word-MATHEMATICS-be-rearranged-such-that-the-word-formed-either-starts-or-ends-with-a-vowel-and-any-three-consecutive-letters-must-contain-a-vowel-

Question Number 110498 by Aina Samuel Temidayo last updated on 29/Aug/20 $$\mathrm{How}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can}\:\mathrm{the}\:\mathrm{letters}\:\mathrm{in}\:\mathrm{the} \\ $$$$\mathrm{word}\:\mathrm{MATHEMATICS}\:\mathrm{be} \\ $$$$\mathrm{rearranged}\:\mathrm{such}\:\mathrm{that}\:\mathrm{the}\:\mathrm{word}\:\mathrm{formed} \\ $$$$\mathrm{either}\:\mathrm{starts}\:\mathrm{or}\:\mathrm{ends}\:\mathrm{with}\:\mathrm{a}\:\mathrm{vowel},\:\mathrm{and} \\ $$$$\mathrm{any}\:\mathrm{three}\:\mathrm{consecutive}\:\mathrm{letters}\:\mathrm{must} \\ $$$$\mathrm{contain}\:\mathrm{a}\:\mathrm{vowel}? \\ $$ Commented…

in-how-many-ways-can-you-put-40-identical-balls-into-20-identical-boxes-such-that-each-box-obtains-at-least-one-ball-and-at-most-5-balls-

Question Number 175567 by mr W last updated on 02/Sep/22 $${in}\:{how}\:{many}\:{ways}\:{can}\:{you}\:{put}\:\mathrm{40} \\ $$$${identical}\:{balls}\:{into}\:\mathrm{20}\:{identical}\:{boxes} \\ $$$${such}\:{that}\:{each}\:{box}\:{obtains}\:{at}\:{least}\:{one} \\ $$$${ball}\:{and}\:{at}\:{most}\:\mathrm{5}\:{balls}? \\ $$ Terms of Service Privacy Policy Contact:…

How-many-are-the-permutations-of-1-a-little-rubik-s-cube-with-4-squares-by-side-2-a-classical-one-with-9-squares-by-side-

Question Number 109488 by bubugne last updated on 24/Aug/20 $${How}\:{many}\:{are}\:{the}\:{permutations}\:{of} \\ $$$$\mathrm{1}\:−\:{a}\:{little}\:{rubik}'{s}\:{cube}\:{with}\:\mathrm{4}\:{squares}\:{by}\:{side} \\ $$$$\mathrm{2}\:−\:{a}\:{classical}\:{one}\:{with}\:\mathrm{9}\:{squares}\:{by}\:{side} \\ $$ Terms of Service Privacy Policy Contact: info@tinkutara.com