Results 1 to 2 of 2

Math Help - compound problem 1/2 way done

  1. #1
    Newbie
    Joined
    Apr 2008
    Posts
    1

    compound problem 1/2 way done

    me & my friend still cannot figure out this problem we have tried to put in the decimals into the calculator but we get diff answers and none of them work yet!

    find the time required for an investment of 5000 dollars to grow 9000 dollars at an interest rate of 7.5 percent per year compounded quarterly.

    answer in t ___ years.



    9000=5000(1+.075/4)^4t

    divide by 5000
    1.8= (1+.075/4)^4t

    then ln1.8 =ln(1+.075/4)^4t

    divide by 4 (1+.075/4) to get t alone.

    ln1.8/4ln(1+.075/4) =T



    i either get .0027 ,.0743, or 7.9 and none are accepted!

    help!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Oct 2007
    From
    London / Cambridge
    Posts
    591
    find the time required for an investment of 5000 dollars to grow 9000 dollars at an interest rate of 7.5 percent per year compounded quarterly.

    It is compounded at a rate of 7.5 \% per quarter, so after each quarter you will have 107.5 \% of your original investment.

    so your equation should be.

    (1.075)^{4t} = 1.8

    As the investment is compounded quarterly and not continuously it would not make sense to submit an answer like 1.345 (I am not suggesting this is the answer, as it is not). Only answer of the form x.25 x.5 or x.75 make sense.

    Hope this helps

    Bobak
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Compound Interest problem
    Posted in the Business Math Forum
    Replies: 0
    Last Post: May 15th 2011, 11:51 PM
  2. Word Problem using compound
    Posted in the Business Math Forum
    Replies: 3
    Last Post: December 30th 2010, 10:34 PM
  3. Compound interest problem
    Posted in the Pre-Calculus Forum
    Replies: 12
    Last Post: December 11th 2009, 03:41 PM
  4. Compound Interest problem..please help..
    Posted in the Business Math Forum
    Replies: 2
    Last Post: September 1st 2009, 09:19 AM
  5. compound interest problem
    Posted in the Business Math Forum
    Replies: 1
    Last Post: October 31st 2008, 04:42 AM

Search Tags


/mathhelpforum @mathhelpforum