A system may become infected by some spyware through the int

A system may become infected by some spyware through the internet or e-mail. Seventy

percent of the time the spyware arrives via the internet, thirty percent of the time via

email. If it enters via the internet, the system detects it immediately with probability

0.6. If via e-mail, it is detected with probability 0.8. What percentage of times is this

spyware detected?

USING LAW OF TOTAL - Please STEP BY STEP!

Using the law of total probability find

P(S)

=P(I/D1)P(D1)+P(E/D1)P(D1) {E denotes email. I denotes internet, D denotes detection}

=0.70*0.6+0.30*0.8

=0.66