The probability an HP network server is down is 0062 If you

The probability an HP network server is down is 0.062. If you have four independent servers, what is the probability that at least one of them is operational?

Solution

P(server is down)=0.062

P(server is working)=1-0.062=0.938

P(atleast one is opertaional)=0.938*0.062^3+0.938^2*0.062^2+0.938^3*0.068+0.0938^4

=0.000294+0.00338+0.0511+0.77412=0.8288