Question 1042662
n=Noe^kt
80,000,000=2,000,000e^k*80
divide by 2000000
40=e^80t
ln of both sides
ln 40=80t
t=ln 40/80
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doubling, n=2No
2No=Noe^kt
2=e^(ln40/80)*t
ln 2=[ln (40)/80]t
divide both sides by ln (40)/80. That inverts the denominator.
80[ln 2/ln40]=t
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A=Ao{1+r/n}^nt
=5000{1+.10/12}^36
=5000(1.08333}^36
the exact answer is 5000{12.1/12)^36