The probability that a bulb produced by a factory will fuse after 150 days of used is 0.05. Find the probability that out of 5 such bulbs
(iv) atleast one will fuse after 150 days of use
Let X represents the number of bulbs that will fuse after 150 days of use in an experiment of 5 trails. The trials are Bernoulli trails.
p=P(success) = 0.05 and q = 1-p=1-0.05 = 0.95
X has a binomial distrubtion with n= 5, p=0.05 and q=0.95
P(X=r) = 5Cr.(0.05)r(0.95)5−r
(iv) Required probability = P(atleast one) = =P(X≥1)=1−P(0)=1−(0.95)5