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Category: Permutation and Combination

Let-A-1-2-3-n-if-a-i-is-the-minimum-element-of-the-set-A-where-A-denotes-the-subset-of-A-containing-exactly-three-elements-and-X-denotes-the-set-of-A-i-s-then-evaluate-A-i-X-

Question Number 22044 by Tinkutara last updated on 10/Oct/17 $$\mathrm{Let}\:{A}\:=\:\left\{\mathrm{1},\:\mathrm{2},\:\mathrm{3},\:…..,\:{n}\right\},\:\mathrm{if}\:{a}_{{i}} \:\mathrm{is}\:\mathrm{the} \\ $$$$\mathrm{minimum}\:\mathrm{element}\:\mathrm{of}\:\mathrm{the}\:\mathrm{set}\:{A};\:\left(\mathrm{where}\right. \\ $$$${A};\:\mathrm{denotes}\:\mathrm{the}\:\mathrm{subset}\:\mathrm{of}\:{A}\:\mathrm{containing} \\ $$$$\left.\mathrm{exactly}\:\mathrm{three}\:\mathrm{elements}\right)\:\mathrm{and}\:{X}\:\mathrm{denotes} \\ $$$$\mathrm{the}\:\mathrm{set}\:\mathrm{of}\:{A}_{{i}} '\mathrm{s},\:\mathrm{then}\:\mathrm{evaluate}\:\underset{{A}_{{i}} \in{X}} {\sum}{a}. \\ $$ Answered…

Determine-the-number-of-ordered-pairs-of-positive-integers-a-b-such-that-the-least-common-multiple-of-a-and-b-is-2-3-5-7-11-13-

Question Number 22042 by Tinkutara last updated on 10/Oct/17 $$\mathrm{Determine}\:\mathrm{the}\:\mathrm{number}\:\mathrm{of}\:\mathrm{ordered} \\ $$$$\mathrm{pairs}\:\mathrm{of}\:\mathrm{positive}\:\mathrm{integers}\:\left({a},\:{b}\right)\:\mathrm{such} \\ $$$$\mathrm{that}\:\mathrm{the}\:\mathrm{least}\:\mathrm{common}\:\mathrm{multiple}\:\mathrm{of}\:{a} \\ $$$$\mathrm{and}\:{b}\:\mathrm{is}\:\mathrm{2}^{\mathrm{3}} \centerdot\mathrm{5}^{\mathrm{7}} \centerdot\mathrm{11}^{\mathrm{13}} . \\ $$ Answered by Rasheed.Sindhi last…

In-how-many-ways-we-can-choose-3-squares-on-a-chess-board-such-that-one-of-the-squares-has-its-two-sides-common-to-other-two-squares-

Question Number 22043 by Tinkutara last updated on 10/Oct/17 $$\mathrm{In}\:\mathrm{how}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{we}\:\mathrm{can}\:\mathrm{choose}\:\mathrm{3} \\ $$$$\mathrm{squares}\:\mathrm{on}\:\mathrm{a}\:\mathrm{chess}\:\mathrm{board}\:\mathrm{such}\:\mathrm{that}\:\mathrm{one} \\ $$$$\mathrm{of}\:\mathrm{the}\:\mathrm{squares}\:\mathrm{has}\:\mathrm{its}\:\mathrm{two}\:\mathrm{sides}\:\mathrm{common} \\ $$$$\mathrm{to}\:\mathrm{other}\:\mathrm{two}\:\mathrm{squares}? \\ $$ Answered by Rasheed.Sindhi last updated on 10/Oct/17…

On-the-modified-chess-board-10-10-Amit-and-Suresh-two-persons-which-start-moving-towards-each-other-Each-person-moving-with-same-constant-speed-Amit-can-move-only-to-the-right-and-upwards-along-t

Question Number 22041 by Tinkutara last updated on 10/Oct/17 $$\mathrm{On}\:\mathrm{the}\:\mathrm{modified}\:\mathrm{chess}\:\mathrm{board}\:\mathrm{10}\:×\:\mathrm{10}, \\ $$$$\mathrm{Amit}\:\mathrm{and}\:\mathrm{Suresh}\:\mathrm{two}\:\mathrm{persons}\:\mathrm{which} \\ $$$$\mathrm{start}\:\mathrm{moving}\:\mathrm{towards}\:\mathrm{each}\:\mathrm{other}.\:\mathrm{Each} \\ $$$$\mathrm{person}\:\mathrm{moving}\:\mathrm{with}\:\mathrm{same}\:\mathrm{constant} \\ $$$$\mathrm{speed}.\:\mathrm{Amit}\:\mathrm{can}\:\mathrm{move}\:\mathrm{only}\:\mathrm{to}\:\mathrm{the} \\ $$$$\mathrm{right}\:\mathrm{and}\:\mathrm{upwards}\:\mathrm{along}\:\mathrm{the}\:\mathrm{lines} \\ $$$$\mathrm{while}\:\mathrm{Suresh}\:\mathrm{can}\:\mathrm{move}\:\mathrm{only}\:\mathrm{to}\:\mathrm{the}\:\mathrm{left} \\ $$$$\mathrm{or}\:\mathrm{downwards}\:\mathrm{along}\:\mathrm{the}\:\mathrm{lines}\:\mathrm{of}\:\mathrm{the} \\…

The-total-number-of-non-similar-triangles-which-can-be-formed-such-that-all-the-angles-of-the-triangle-are-integers-is-

Question Number 22040 by Tinkutara last updated on 10/Oct/17 $$\mathrm{The}\:\mathrm{total}\:\mathrm{number}\:\mathrm{of}\:\mathrm{non}-\mathrm{similar} \\ $$$$\mathrm{triangles}\:\mathrm{which}\:\mathrm{can}\:\mathrm{be}\:\mathrm{formed}\:\mathrm{such} \\ $$$$\mathrm{that}\:\mathrm{all}\:\mathrm{the}\:\mathrm{angles}\:\mathrm{of}\:\mathrm{the}\:\mathrm{triangle}\:\mathrm{are} \\ $$$$\mathrm{integers}\:\mathrm{is} \\ $$ Commented by mrW1 last updated on 01/Jan/18…

The-symbols-are-placed-in-the-squares-of-the-adjoining-figure-The-number-of-ways-of-placing-symbols-so-that-no-row-remains-empty-is-

Question Number 22038 by Tinkutara last updated on 10/Oct/17 $$\mathrm{The}\:\mathrm{symbols}\:+,\:+,\:×,\:×,\:\bigstar,\:\bullet,\:\mathrm{are} \\ $$$$\mathrm{placed}\:\mathrm{in}\:\mathrm{the}\:\mathrm{squares}\:\mathrm{of}\:\mathrm{the}\:\mathrm{adjoining} \\ $$$$\mathrm{figure}.\:\mathrm{The}\:\mathrm{number}\:\mathrm{of}\:\mathrm{ways}\:\mathrm{of}\:\mathrm{placing} \\ $$$$\mathrm{symbols}\:\mathrm{so}\:\mathrm{that}\:\mathrm{no}\:\mathrm{row}\:\mathrm{remains}\:\mathrm{empty} \\ $$$$\mathrm{is} \\ $$ Commented by Tinkutara last updated…

How-many-5-digit-numbers-from-the-digits-0-1-9-have-i-Strictly-increasing-digits-ii-Strictly-increasing-or-decreasing-digits-iii-Increasing-digits-iv-Increasing-or-decreasing-digit

Question Number 22037 by Tinkutara last updated on 10/Oct/17 $$\mathrm{How}\:\mathrm{many}\:\mathrm{5}-\mathrm{digit}\:\mathrm{numbers}\:\mathrm{from}\:\mathrm{the} \\ $$$$\mathrm{digits}\:\left\{\mathrm{0},\:\mathrm{1},\:…..,\:\mathrm{9}\right\}\:\mathrm{have}? \\ $$$$\left(\mathrm{i}\right)\:\mathrm{Strictly}\:\mathrm{increasing}\:\mathrm{digits} \\ $$$$\left(\mathrm{ii}\right)\:\mathrm{Strictly}\:\mathrm{increasing}\:\mathrm{or}\:\mathrm{decreasing} \\ $$$$\mathrm{digits} \\ $$$$\left(\mathrm{iii}\right)\:\mathrm{Increasing}\:\mathrm{digits} \\ $$$$\left(\mathrm{iv}\right)\:\mathrm{Increasing}\:\mathrm{or}\:\mathrm{decreasing}\:\mathrm{digits} \\ $$ Commented…

The-number-of-five-digits-can-be-made-with-the-digits-1-2-3-each-of-which-can-be-used-atmost-thrice-in-a-number-is-

Question Number 22035 by Tinkutara last updated on 10/Oct/17 $$\mathrm{The}\:\mathrm{number}\:\mathrm{of}\:\mathrm{five}\:\mathrm{digits}\:\mathrm{can}\:\mathrm{be}\:\mathrm{made} \\ $$$$\mathrm{with}\:\mathrm{the}\:\mathrm{digits}\:\mathrm{1},\:\mathrm{2},\:\mathrm{3}\:\mathrm{each}\:\mathrm{of}\:\mathrm{which}\:\mathrm{can} \\ $$$$\mathrm{be}\:\mathrm{used}\:\mathrm{atmost}\:\mathrm{thrice}\:\mathrm{in}\:\mathrm{a}\:\mathrm{number}\:\mathrm{is} \\ $$ Terms of Service Privacy Policy Contact: info@tinkutara.com