7. (5 points) A computer is infected with a 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?
2007-11-05 13:52:30 · 2 answers · asked by Hope C 1 in Science & Mathematics ➔ Mathematics
20 ^ X = 100,000,000
X = log 100,000,000 / log 20 = 6.148.
6.148 x 5min = 30.75 minutes
2007-11-05 14:09:03 · answer #1 · answered by davidosterberg1 6 · 0⤊ 0⤋
Since each 5 minutes corresponds to a multiple of 20,
20^K = 10^8 where K is a multiple of 5 minutes. Taking logs of both sides,
K log20 = 8 (base 10)
Since log 20 = 1.3 (appx), K = 8/1.3 or slightly more than 6. So the answer is about 30+ minutes.
2007-11-05 22:04:56 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋