20 cards are numbered from 1 to 20. One card is drawn at random. What is the probability that the number on the cards is:

(i) a multiple of 4?


(ii) not a multiple of 4?


(iii) odd?


(iv) greater than 12?


(v) divisible by 5?


(vi) not a multiple of 6?

given: 20 cards numbered from 1-20

formula:


one card is drawn at random therefore total possible outcomes are 20C1


therefore n(S)=20C1=20


(i) let E be the event that the number on the drawn card is a multiple of 4


E= {4, 8, 12, 16, 20}


n(E)= 5C1=5




(ii) let E be the event that the number on the drawn card is not a multiple of 4


E’ be the event that the number on the drawn card is a multiple of 4


E’= {4, 8, 12, 16, 20}


n(E)= 5C1=5




P(E)=1-P(E’)



(iii) let E be the event that the number on the drawn card is odd


E= {1, 3, 5, 7, 9, 11, 13, 15, 17, 19}


n(E)= 10C1=10




(iv) let E be the event that the number on the drawn card is greater than 12


E= {13, 14, 15, 16, 17, 18, 19, 20}


n(E)= 8C1=8




(v) let E be the event that the number on the drawn card is a multiple of 5


E= {5, 10, 15, 20}


n(E)= 4C1=4




(vi) let E be the event that the number on the drawn card is not divisible by 6


let E’ be the event that number on the drawn card is divisible by 6


E’= {6, 12, 18}


n(E’)= 3C1=3




P(E)=1-P(E’)



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