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Showing posts from January 2, 2019

did i solve these counting problems correctly? [closed]

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0 1 nine people (Ann, Ben, Cal, Dot, Ed, Fran, Gail, Hal, and Ida) are in a room. Five of them stand in a row for a picture. a) In how many ways can this be done if both Ed and Gail are in the picture? P(5,2)= 5×4 = 20 b) In how many ways can this be done if neither Ed nor Fran are in the picture? P(5,3)= 5×4×3= 60 c) In how many ways can this be done if Dot is on the left end and Ed is on the right end? P(5,3)= 5×4×3= 60 d) In how many ways can this be done if Hal or Ida (but not both) are in the picture? P(5,4) + P(5,4)= 120+120= 240 e) In how many ways can this be done if Ed and Gail are in the picture, standing next to each other? P(5,4)= 120 Thank you discrete-mathematics share | cite

NASCAR Grand National de 1958

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A Temporada da NASCAR Grand National de 1958 foi a décima edição da Nascar, com 51 etapas disputadas o campeão foi Lee Petty. [ 1 ] Índice 1 Calendário 2 Classificação final 3 Referências 4 Ligações externas Calendário | N. Data Corrida Circuito Campeão Segundo Terceiro 1 3-nov Race 1 Champion Speedway Rex White Lee Petty Tiny Lund 2 23-feb Race 2 Daytona Beach & Road Course Paul Goldsmith Curtis Turner Jack Smith 3 2-mrt Race 3 Concord Speedway Lee Petty Curtis Turner Speedy Thompson 4 15-mrt Race 4 Champion Speedway Curtis Turner Gwyn Staley Buck Baker 5 16-mrt Race 5 Wilson Speedway Lee Petty Buck Baker Marvin Panch 6 23-mrt Race 6 Occoneechee Speedway Buck Baker Marvin Panch Speedy Thompson 7 5-apr Race 7 Champion Speedway Bob Welborn Frankie Schneider Speedy Thompson 8 10-apr Race 8 Columbia Speedway Speedy Thompson Jack Smith Tiny Lund

Can we state the existence of infinite set without infinity axiom? [duplicate]

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0 This question already has an answer here: Using the Definition of Dedekind-Infinite to Replace the Axiom of Infinity 2 answers How can I define $mathbb{N}$ if I postulate existence of a Dedekind-infinite set rather than existence of an inductive set? 2 answers I have a question about infinity axiom in ZF and maybe, it has nonsense. So I apologize in advance if it is the case. In ZF , the infiny axiom can be state as $exists X(Xneqemptysetwedgeforall xin X(S(x)in X))$ and it says that exists an infinite set (moreover, it is equivalent to say that $omega$ exists) more exactly, it says that exists an inductive set. In this l