SOLUTION: Given: There are 7.3 billion, that is, 7.3*109 people on Earth. If a flu virus starts with one person and within 1 day four more people are infected, then each of those four pe

Algebra ->  Logarithm Solvers, Trainers and Word Problems -> SOLUTION: Given: There are 7.3 billion, that is, 7.3*109 people on Earth. If a flu virus starts with one person and within 1 day four more people are infected, then each of those four pe      Log On


   



Question 744744: Given: There are 7.3 billion, that is, 7.3*109
people on Earth. If a flu virus starts
with one person and within 1 day four more
people are infected, then each of those four
people in 1 day infects 4 people each,
and so on, how many days before everyone
on earth is infected?

Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
This is an exponential growth problem where the population quadruples every day. Our model equation is:
P=P%5B0%5D%2A4%5Et

with
P%5B0%5D=1, P=7.3x10%5E9
which leads to...
7300000000=4%5Et

log7300000000=log+%284%5Et%29

t=%28log7300000000%29%2Flog4
t is about...16.4 days