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Category: Permutation and Combination

In-how-many-ways-can-a-committee-of-11-people-be-selected-from-9-people-

Question Number 35165 by NECx last updated on 16/May/18 $${In}\:{how}\:{many}\:{ways}\:{can}\:{a}\:{committee} \\ $$$${of}\:\mathrm{11}\:{people}\:{be}\:{selected}\:{from}\:\mathrm{9} \\ $$$${people}. \\ $$ Commented by Rasheed.Sindhi last updated on 16/May/18 $$\mathrm{How}\:\mathrm{can}\:\mathrm{we}\:\mathrm{select}\:\mathrm{a}\:\mathrm{committee}\:\mathrm{of}\:\mathrm{11} \\…

Question-35151

Question Number 35151 by Victor31926 last updated on 16/May/18 Answered by Rasheed.Sindhi last updated on 16/May/18 $$\because\mathrm{5}\mid\mathrm{5}!\:\&\:\mathrm{5}!\:\mid\:\mathrm{50}!,\mathrm{40}!,\mathrm{30}!,\mathrm{20}!,\mathrm{10}! \\ $$$$\therefore\:\mathrm{5}\mid\:\mathrm{50}!,\mathrm{40}!,\mathrm{30}!,\mathrm{20}!,\mathrm{10}! \\ $$$$\:\therefore\mathrm{5}\mid\:\left(\mathrm{50}!+\mathrm{40}!+\mathrm{30}!+\mathrm{20}!+\mathrm{10}!\right) \\ $$$$\therefore\:\mathrm{The}\:\mathrm{remainder}=\mathrm{0} \\ $$…

A-committee-of-4-is-to-be-formed-from-4-principals-and-5-students-In-how-many-ways-can-this-be-done-if-a-particular-student-and-a-principal-must-be-in-the-committee-

Question Number 34930 by NECx last updated on 13/May/18 $${A}\:{committee}\:{of}\:\mathrm{4}\:{is}\:{to}\:{be}\:{formed} \\ $$$${from}\:\mathrm{4}\:{principals} \\ $$$${and}\:\mathrm{5}\:{students}.{In}\:{how}\:{many}\:{ways} \\ $$$${can}\:{this}\:{be}\:{done}\:{if}\:{a}\:{particular} \\ $$$${student}\:{and}\:{a}\:{principal}\:{must}\:{be} \\ $$$${in}\:{the}\:{committee}. \\ $$$$ \\ $$ Commented…

4-couples-are-to-take-a-photograph-with-a-newly-wedded-couple-in-a-wedding-party-In-how-many-ways-can-this-be-done-if-i-the-celebrated-couple-must-stand-in-the-middle-ii-each-couple-must-stand-next-t

Question Number 34877 by NECx last updated on 12/May/18 $$\mathrm{4}\:{couples}\:{are}\:{to}\:{take}\:{a}\:{photograph} \\ $$$${with}\:{a}\:{newly}\:{wedded}\:{couple}\:{in}\:{a} \\ $$$${wedding}\:{party}.{In}\:{how}\:{many}\:{ways} \\ $$$${can}\:{this}\:{be}\:{done}\:{if}: \\ $$$$\left.{i}\right){the}\:{celebrated}\:{couple}\:{must}\:{stand} \\ $$$${in}\:{the}\:{middle} \\ $$$$\left.{ii}\right){each}\:{couple}\:{must}\:{stand}\:{next}\:{to} \\ $$$${each}\:{other} \\…

A-certain-wire-has-length-4-5-cm-and-mass-12-3-g-with-an-electrical-resistance-of-1-1-m-this-wire-falls-through-a-horizontal-magnetic-field-with-flux-density-of-0-35-T-As-his-wire-falls-its-ends

Question Number 99985 by Rio Michael last updated on 24/Jun/20 $$\mathrm{A}\:\mathrm{certain}\:\mathrm{wire}\:\mathrm{has}\:\mathrm{length}\:\mathrm{4}.\mathrm{5}\:\mathrm{cm}\:\mathrm{and}\:\mathrm{mass}\:\mathrm{12}.\mathrm{3}\:\mathrm{g},\:\:\mathrm{with}\:\mathrm{an} \\ $$$$\mathrm{electrical}\:\mathrm{resistance}\:\mathrm{of}\:\mathrm{1}.\mathrm{1}\:\mathrm{m}\Omega.\:\mathrm{this}\:\mathrm{wire}\:\mathrm{falls}\:\mathrm{through}\:\mathrm{a}\:\mathrm{horizontal} \\ $$$$\mathrm{magnetic}\:\mathrm{field}\:\:\mathrm{with}\:\mathrm{flux}\:\mathrm{density}\:\mathrm{of}\:\mathrm{0}.\mathrm{35}\:\mathrm{T}.\:\mathrm{As}\:\mathrm{his}\:\mathrm{wire}\:\mathrm{falls}\:\mathrm{its}\:\mathrm{ends} \\ $$$$\mathrm{slide}\:\mathrm{smoothly}\:\mathrm{between}\:\mathrm{two}\:\mathrm{rails}\:\mathrm{connected}\:\mathrm{by}\:\mathrm{a}\:\mathrm{wire}\:\mathrm{with}\:\mathrm{negligible} \\ $$$$\mathrm{internal}\:\mathrm{resistance}.\:\mathrm{Calculate}\:\mathrm{the}\:\mathrm{magnitude}\:\mathrm{of}\:\mathrm{the}\:\mathrm{terminal}\:\mathrm{energy} \\ $$$$\mathrm{resistance},\:\mathrm{neglecting}\:\mathrm{the}\:\mathrm{resistance}\:\mathrm{of}\:\mathrm{the}\:\mathrm{rails}. \\ $$ Terms of…

Question-99905

Question Number 99905 by Rio Michael last updated on 23/Jun/20 Commented by Rio Michael last updated on 23/Jun/20 $$\mathrm{P}\:\mathrm{and}\:{Q}\:\mathrm{are}\:\mathrm{two}\:\mathrm{identical}\:\mathrm{straight}\:\mathrm{cables}\:\mathrm{each}\:\mathrm{of}\:\mathrm{electrical}\:\mathrm{resistance}\:\mathrm{20}.\mathrm{0}\Omega. \\ $$$$\mathrm{placed}\:\mathrm{4}.\mathrm{8}\:\mathrm{cm}\:\mathrm{apart}\:\mathrm{in}\:\mathrm{air}.\: \\ $$$$\left(\mathrm{a}\right)\:\mathrm{find}\:\mathrm{the}\:\mathrm{current}\:\mathrm{through}\:\mathrm{each}\:\mathrm{cable} \\ $$$$\left(\mathrm{b}\right)\:\mathrm{draw}\:\mathrm{the}\:\mathrm{magnetic}\:\mathrm{field}\:\mathrm{pattern}\:\mathrm{in}\:\mathrm{the}\:\mathrm{region}\:\mathrm{between}\:{P}\:\mathrm{and}\:{Q}…

Number-of-ways-n-differrnt-things-be-distributed-in-r-identical-boxes-so-as-1-empty-box-is-allowed-2-empty-box-not-allowed-Number-of-ways-n-identical-things-be-distributed-to-r-identical-boxes-s

Question Number 165385 by SLVR last updated on 31/Jan/22 $${Number}\:{of}\:\:{ways}..{n}\: \\ $$$${differrnt}\:\:{things}\:{be}\:{distributed} \\ $$$${in}\:{r}\:{identical}\:{boxes}\:{so}\:{as} \\ $$$$\left.\mathrm{1}\right){empty}\:{box}\:{is}\:{allowed} \\ $$$$\left.\mathrm{2}\right){empty}\:{box}\:{not}\:{allowed} \\ $$$${Number}\:{of}\:{ways}…{n}\:{identical} \\ $$$${things}\:{be}\:{distributed}\:{to}\:{r} \\ $$$${identical}\:{boxes}\:{so}\:{as} \\…