Question 1170810
A=Ao(1+r)^35, r is the rate. A/Ao=2, since it is doubling.
2=(1+r)^35
ln both sides
ln2=35*ln(1+r)
0.0198=ln(1+r). Don't round
raise both sides to the e power
1.02000=1+r
r=2.0%
Consistent with rule of 70, which is 70/2%=35 years to double
2120 is 40 years
A=(1.02)^40*4.5 to get answer
=9.936 billion.