Find the interest rate needed for an investment of $7,000 to grow to $10,500 in 6 yr if interest is compounded monthly. (Round your answer to the nearest hundredth of a percentage point.)

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- November 15th 2010, 12:25 PMdjdownfawlInterest Rate
Find the interest rate needed for an investment of $7,000 to grow to $10,500 in 6 yr if interest is compounded monthly. (Round your answer to the nearest hundredth of a percentage point.)

- November 15th 2010, 12:39 PMemakarov
You are supposed to show some effort. Do you know the formula for the total amount after n month? If yes, what is your difficulty?

- November 15th 2010, 12:46 PMdjdownfawl
a = p (1+ r/m) ^mt

?? - November 15th 2010, 02:15 PMemakarov
Yes, so , i.e., . By raising both sides to 1/72, you can find r.

- November 17th 2010, 12:45 PMdjdownfawl
idk how to take the log and find r...

- November 17th 2010, 12:49 PMdjdownfawl
do u want me to take 72th root of both sides?

- November 17th 2010, 12:52 PMdjdownfawl
if i take the 72th root of both sides then r = 0 ...?

- November 17th 2010, 01:08 PMemakarovQuote:

if i take the 72th root of both sides then r = 0 ...?

- November 17th 2010, 01:09 PMdjdownfawl
ok i got it..

thanks the answer came out right..

r = 6.80 rounded - November 17th 2010, 01:11 PMdjdownfawl
But the other problem i am not able to figure out and i have 1 more try left its the last one..

can you please help - November 17th 2010, 01:11 PMdjdownfawl
Use logarithms to solve the equation for

*t*. http://www.webassign.net/cgi-bin/sym...%2F2%29%29%3DC - November 17th 2010, 01:32 PMemakarov
iff

and .

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or .

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. - November 17th 2010, 01:39 PMdjdownfawl
SO T = 2ln((A-C)/BC))

right? - November 17th 2010, 01:40 PMdjdownfawl
yessssssss its right!!!

thankkkk kyouuuuu soo muchhhh i appreciate your help very muchhhhh - November 17th 2010, 01:56 PMemakarov
You are welcome.