Question 478250
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Hi,
5 ill week 1, each spreading to 4 people by the end of the next week...
By the end of the tenth week of the epidemic, how many people have been
 affected by the illness?
{5,20,80,320,...}
Geometric sequence r = 4
{{{a[n] = 5*4^(n-1)}}}
{{{sum( a[n], n=1, 10 )}}} = a(1-r^n)/(1-r)= 5(1-4^10)/(1-4) = 1,747,625