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Question 59960: I need some help on this question, I keep on getting confused can u please help?
Thanks in advance
A computer is infected with the Sasser virus. Assume that it infects 20 other computers within 5 minutes; and that these PCs and servers each infect 20 more machines within another five minutes, etc. How long until 100 million computers are infected?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A computer is infected with the Sasser virus. Assume that it infects 20 other computers within 5 minutes; and that these PCs and servers each infect 20 more machines within another five minutes, etc. How long until 100 million computers are infected?
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1st: 20
2nd: 20^2
3rd: 2^3
etc
This is a geometric series
Formula:
Sum = a(r^(n+1)-1)/(r-1)
Sum= 100 million
a=20
r=20
Find n
100 mill = 20 (20^(n+1)-1)/(20-1)
19*5 mill + 1 = 20^(n+1)
Take the log of both sides to get:
7.97772361... =(n+1)0.1142873095...
n+1=69.80410727
n=68.80
time = 68.80*5 minutes = 344.02 minutes
time = 5.733 hours
Cheers,
Stan H.
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