Answer:
0.623 is the probability that between 800 and 850 files get damaged.
Step-by-step explanation:
We are given the following information:
We treat virus can damage computer as a success.
P( virus can damage computer) = 35% = 0.35
The conditions for normal distribution are satisfied.
By normal approximation:

We have to evaluate probability that between 800 and 850 files get damaged.


0.623 is the probability that between 800 and 850 files get damaged.
1) is ABC and XYZ
2) is ABC and RQP I’m not sure about this one though
The full answer is 20.125 but it says to round so the answer is C. 20.13