In: Statistics and Probability
A earton of 12 transistor batteries contains 4 that
are defective. In how many different ways can one choose 3 of these
batteries so that
a) none of the defective batteries is included
b) exactly 1 of the defective batteries is included
c) exactly 2 of the defective batteries are included
d) exactly 3 of the defective batteries are included
total number of transistor batteries = 12
number of defective batteries = 4
number of good batteries = (12-4) = 8
a).number of ways none of the defective batteries is included is:-
[ we will select all the 3 batteries from 8 good batteries ]
b).number of ways exactly 1 of the defective batteries is included is:-
[ select 1 defective batteries from 4 defective batteries and rest (3-1) = 2 batteries from 8 good batteries ]
c).number of ways exactly 2 of the defective batteries is included is:-
[ select 2 defective batteries from 4 defective batteries and rest (3-2) = 1 batteries from 8 good batteries ]
d).number of ways exactly 3 of the defective batteries is included is:-
[ select all the 3 defective batteries from 4 defective batteries ]
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