## CesarLovesNadia 3 years ago find the amount of time in years that it will take an investment of \$1000 to double at 8%interest compounded continuosly. (hint A=Pe^rt

1. cshalvey

Hi @CesarLovesNadia - so you know the formula you need to use, correct? Are you able to put them together?

no im not thats why its here i need help

3. cshalvey

No problem, so the interest formula for compound interest is what you have listed. So, A is the number we are looking for, we have the rest. So, A = P (principal amount) x e (Napier's #, roughly 2.7183) ^ r (interest rate) x t (number of years). So, how about you try and put in the numbers you know, and I can help you with anything you don't understand?

4. cshalvey

For the 'e' - your calculator will actually have this number built in, so don't worry about it for now :)

how many years would it be?

7. cshalvey

@CesarLovesNadia - You have to learn how to do these problems - I'm not here to give you the answer. I WILL help you get there though, I promise. Can you try and put the variables from the word problem into the equation now?

i diid i put 1000*2.7183^(0.08*1)

it came out to be like 1000 something

10. cshalvey

No worries - and good start. The problem states that you need to find the time, t, for your money to double. Therefore, you know that A = 2xP = 2000. So, your equation looks like this: $2000 = 1000*e^(.08*t)$

so then wait

the answer would be 2000 then?

13. ParthKohli

Colm, it'd be $$2000 = 1000 \times e^{(0.8 \times t)}$$ Sorry for interfering, guys.

thanks

15. ParthKohli

@CesarLovesNadia You should appreciate Colm for helping you :) P.S. He's the major part behind OpenStudy ;)

16. cshalvey

Heh, that's what I was writing - guess it showed up wrong. And no, @CesarLovesNadia you need to find the TIME, t in this equation, right? "find the amount of time in years"

but what is it then?

just help me and give me the answer

19. cshalvey

@CesarLovesNadia - sorry, but you should read the Code of Conduct ( http://openstudy.com/code-of-conduct) - we don't just give the answer. I can help you understand it though :) So now, you have to solve for T in that equation I and Parth just gave you. Can you start that?

so would it be 2?

is it 2?

22. ParthKohli

Heh—don't give me the credit. Keep it on, guys!

help me with another one

24. cshalvey

Given your equation 2000 = 1000 x e^(.08xT) We divide both sides by 1000 to give us this: 2 = e^(.08xT)

25. ParthKohli
26. ParthKohli

Your Math is pretty good, Colm!

27. cshalvey

@CesarLovesNadia - you'll probably want to use that link to get the real answer. Hint - it's not two.