Question

. 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

Answer 1

Answer:

This spyware is detected 66% of the time.

Step-by-step explanation:

We have these following percentages:

70% of the time, the spyware arrives via the internet, and in this case, is detected 60% of the time.

30% of the time, the spyware arrives via e-mail, and in this case, is detected 80% of the time.

What percentage of times is this spyware detected

Sum of 60% of 70%(arrived via spyware, detecte) and 80% of 30%(arrive via e-mail, detected). So

$0.6*0.7 + 0.8*0.3 = 0.42 + 0.24 = 0.66$

This spyware is detected 66% of the time.