Question

adam put $100 in a savings account after 10 years he had $1649 in the account what rate of interest did he earn? use the formula a=pe^rt where a is the ending amount p is the principal (initial amount) r is the interest rate and t is the time

Answer 1

using the formula
ending amount is 1649=a
p=initial amount=100
t=10
r=r

so
1649=100e^{10r}
divide both sides by 100
16.49=e^{10r}
take ln of both sides
ln(16.49)=10r
divide both sides by 10
(ln(16.49))/10=r
use calculator
0.28027=r
about 28% interest