A woman deposits $50,000 in a savings account with 4% continuously compounded interest. How many years must she wait until the balance has doubled?
Assume that the number of viruses present in a sample is modeled by the exponential function "f(t) = 10t," where t is the elapsed time in minutes. How would you apply logarithms to determine when the sample will grow to 5 billion viruses?
THANKS FOR THE HELP
2007-09-19 04:48:40 · 4 answers · asked by crackr 3 in Science & Mathematics ➔ Mathematics
HM... i guess i only know the question one....
if got $50,000 with 4% interest... so one year have $2000...
so use $50,000 divided by $2000 equal to 25.... if doubled the amount which mean is $100,000 so need to wait for 25 years. becos originally already have $50,000 in the bank account and plus 4% in every years until the year 25, her bank account will get $100,000....
the question number two i dont understand what it means.... counld you explain it in simple way??
2007-09-19 05:01:55 · answer #1 · answered by some_one_with_love 3 · 0⤊ 1⤋
I don't have a clue about the second question but I think you can use what is called the rule of 72 with the first question. This principle is used when you have a set APR in your case 4% where the original amount will be doubled when a multiple of 72% reaches maturity. 72/4 is 18 so she would have to wait 18 years for her original deposit to be $100,000.
2007-09-19 05:03:21 · answer #2 · answered by Emissary 6 · 0⤊ 1⤋
100000 = 50000e^.04n
2= e^.04n
ln2 =.04n
n = ln(2) /.04 = 17.33 years
You mean f(t) = 10^t
10^t = 5X10^9
log 10^t = log 5X10^9
tlog10 = log5 + log(10^9)
t = 9 +log5 = 9.69897 minutes
2007-09-19 05:25:49 · answer #3 · answered by ironduke8159 7 · 1⤊ 0⤋
A = Pe^rt
100,000=50,000e^(.04x)
2=e^(.04x)
solve for x
use ur math book
2007-09-19 05:07:42 · answer #4 · answered by Anonymous · 0⤊ 0⤋