IIT JEE , AIEEE Forum - Mathematics , Algebra

sweetgal17

a bag consists of 10 balls each marked with one of the digits 0 to 9. if four balls are drawn succesively with replacement from the bag what is the probability tht none is marked with the digit 0.

another question.

an experiment succeeds twice as often it fails. find the probability tht in the next 6 trials there will be atleast 4 successes..

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akhil_o

(9/10) prob that no 0 in one lift
hence in four lifts
we have
(0.9)^4

akhil_o

for second one
prob of successful event=2/3 and non-successful=1/3
hence required prob
=⁶C₄(2/3)⁴(1/3)²+⁶C₅(2/3)⁵(1/3)+⁶C₆(2/3)^₆=496/3⁶

ziauddin75

akhil had done correct

for second one

lets failure be n times
success will be 2n times
total =3n
q=1/3(prob. of failure)
p=2/3(prob of success)
n=6
P(X(atleast 4)=1-P(X=5)-P(=6)
now solve and get the answer

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