Category: Permutation and Combination

Question Number 48341 by Tinkutara last updated on 22/Nov/18 Terms of Service Privacy Policy Contact: info@tinkutara.com

Question Number 113710 by mr W last updated on 14/Sep/20 $$youhave2identicalmathematics$$$$books,2identicalphysicsbooks,2$$$$identicalchemistrybooks,2identical$$$$biologybooksand2geographybooks.$$$$inhowmanywayscanyoucompile$$$$thesebookssuchthatsamebooks$$$$arenotmutuallyadjacent?$$…

Question Number 178937 by Tawa11 last updated on 22/Oct/22 $$\mathrm{Find}\mathrm{the}\mathrm{greatest}\mathrm{coefficient}\mathrm{in}\mathrm{expansion}\mathrm{of}:{(6-4\mathrm{x})}^{-3}$$ Answered by mr W last updated on 23/Oct/22 $${(6-4x)}^{-3}$$$$=\mathrm{6}^{−\mathrm{3}} \left(\mathrm{1}−\frac{\mathrm{2}{x}}{\mathrm{3}}\right)^{−\mathrm{3}} \…

Question Number 113355 by Aina Samuel Temidayo last updated on 12/Sep/20 $$\mathrm{A}\mathrm{rectangular}\mathrm{cardboard}\mathrm{is}8\mathrm{cm}\mathrm{long}$$$$\mathrm{and}6\mathrm{cm}\mathrm{wide}.\mathrm{What}\mathrm{is}\mathrm{the}\mathrm{least}$$$$\mathrm{number}\mathrm{of}\mathrm{beads}\mathrm{you}\mathrm{can}\mathrm{arrange}\mathrm{on}$$$$\mathrm{the}\mathrm{board}\mathrm{such}\mathrm{that}\mathrm{there}\mathrm{are}\mathrm{at}\mathrm{least}$$$$\mathrm{two}\mathrm{of}\mathrm{the}\mathrm{beads}\mathrm{that}\mathrm{are}\mathrm{less}\mathrm{than}$$$$\sqrt{10}\mathrm{cm}\mathrm{apart}.$$ Commented…

Question Number 47656 by Necxx last updated on 12/Nov/18 $$Asquareisdividedinto9identical$$$$smallersquares.Sixidenticalballs$$$$aretobeplacedinthesesmaller$$$$squaressuchthateachofthethree$$$$rowsgetsatleastoneball(one$$$$ballinonesquareonly).Inhow$$$$manydifferentwayscanthisbe$$$${done}? \…