## CesarLovesNadia Group Title 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 2 years ago 2 years ago

1. cshalvey Group Title

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 Group Title

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 Group Title

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 Group Title

@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 Group Title

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 Group Title

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

thanks

15. ParthKohli Group Title

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

16. cshalvey Group Title

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 Group Title

@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 Group Title

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

help me with another one

24. cshalvey Group Title

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

25. ParthKohli Group Title
26. ParthKohli Group Title

Your Math is pretty good, Colm!

27. cshalvey Group Title

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