In a simultaneous throw of a pair of dice, find the probability of getting:

(i) 8 as the sum


(ii) a doublet


(iii) a doublet of prime numbers


(iv) an even number on first


(v) a sum greater than 9


(vi) an even number on first


(vii) an even number on one and a multiple of 3 on the other


(viii) neither 9 nor 11 as the sum of the numbers on the faces


(ix) a sum less than 6


(x) a sum less than 7


(xi) a sum more than 7


(xii) neither a doublet nor a total of 10


(xiii) odd number on the first and 6 on the second


(xiv) a number greater than 4 on each die


(xv) a total of 9 or 11


(xvi) a total greater than 8

given: a pair of dice have been thrown, so the number of elementary events in sample space is 62=36

formula:


therefore n(S)=36


(i) let E be the event that the sum 8 appears


E= {(2,6) (3,5) (4,4) (5,3) (6,2)}


n(E)=5




(ii) let E be the event of getting a doublet


E= {(1,1) (2,2) (3,3) (4,4) (5,5) (6,6)}


n(E)=6




(iii) let E be the event of getting a doublet of prime numbers


E= {((2,2) (3,3) (5,5)}


n(E)=3




(iv) let E be the event of getting a doublet of odd numbers


E= {(1,1) (3,3) (5,5)}


n(E)=3




(v) let E be the event of getting sum greater than 9


E= {(4,6) (5,5) (5,6) (6,4) (6,5) (6,6)}


n(E)=6




(vi) let E be the event of getting even on first die


E= {(2,1) (2,2) (2,3) (2,4) (2,5) (2,6) (4,1) (4,2) (4,3) (4,4) (4,5) (4,6) (6,1) (6,2) (6,3) (6,4) (6,5) (6,6)}


n(E)=18




(vii) let E be the event of getting even on one and multiple of three on other


E= {(2,3) (2,6) (4,3) (4,6) (6,3) (6,6) (3,2) (3,4) (3,6) (6,2) (6,4)}


n(E)=11




(viii) let E be the event of getting neither 9 or 11 as the sum


E= {(3,6) (4,5) (5,4) (5,6) (6,3) (6,5)}


n(E)=6




(ix) let E be the event of getting sum less than 6


E= {(1,1) (1,2) (1,3) (1,4) (2,1) (2,2) (2,3) (3,1) (3,2) (4,1)}


n(E)=10




(x) let E be the event of getting sum less than 7


E= {(1,1) (1,2) (1,3) (1,4) (1,5) (2,1) (2,2) (2,3) (2,4) (3,1) (3,2) (3,3) (4,1) (4,2) (5,1)}


n(E)=15




(xi) let E be the event of getting more than 7


E= {(2,6) (3,5) (3,6) (4,4) (4,5) (4,6) (5,3) (5,4) (5,5) (5,6) (6,2) (6,3) (6,4) (6,5) (6,6)}


n(E)=15




(xii) let E be the event of getting neither a doublet nor a total of 10


E’ be the event that either a doublet or a sum of ten appears


E’= {(1,1) (2,2) (3,3) (4,6) (5,5) (6,4) (6,6) (4,4)}


n(E’) =8




Therefore P(E)=1-P(E’)



(xiii) let E be the event of getting odd number on first and 6 on second


E= {(1,6) (5,6) (3,6)}


n(E)=3




(xiv) let E be the event of getting greater than 4 on each die


E= {(5,5) (5,6) (6,5) (6,6)}


n(E)=4




(xv) let E be the event of getting total of 9 or 11


E= {(3,6) (4,5) (5,4) (5,6) (6,3) (6,5)}


n(E)=6




(xvi) let E be the event of getting total greater than 8


E= {(3,6) (4,5) (4,6) (5,4) (5,5) (5,6) (6,3) (6,4) (6,5) (6,6)}


n(E)=10




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