Question

help with compound interest! please
How long would it take $3,300 to grow to $9,100 if the annual rate is 4.4% and interest in compounded monthly

Answer 1

\[9,100=3,300(1+\frac{.044}{12})^{12t}\] solve for \(t\)

Answer 2

a) divide by 3300 first
b) use the change of base formula
c) divide by 12

Answer 3

do you divide both sides by 3300 or no

Answer 4

yes both sides

Answer 5

\[\frac{91}{33}=(1+\frac{.044}{12})^{12t}\]

Answer 6

then use the fact that \(A+b^x\iff x=\frac{\ln(A)}{\ln(b)}\) to find
\[12t=\frac{\ln(\frac{91}{33})}{\ln(1+\frac{.044}{12})}\]

Answer 7

sorry, i meant
\[A=b^x\iff x=\frac{\ln(A)}{\ln(b)}\]

Answer 8

last step is to divide by 12 and you are done
these questions really all over the map.
on line i am guessing.

Answer 9

23.1 that is rounded... yes online :/

Answer 10

i didn't do it, let me check

Answer 11

yeah that is what i get

Answer 12

cool, if you have time could we try one more? it is slightly different ....
If $6,000 is placed in an account with an annual interest rate of 6%, how long will it take the amount to quadruple if the interest is compounded annually? Round your answer to two decimal places