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Homework Help: Rounding this answer to the nearest tenth.

  1. Oct 25, 2007 #1
    1. The problem statement, all variables and given/known data

    1. What interest rate is required to turn $1000 into $1500 in 5 years if the
    interest is compounded:
    a) annually
    b) monthly
    (round your answer to the nearest tenth of a percent)

    2. Relevant equations

    I'm using the formula: (A/P)^1/n - 1 = i (interest)

    3. The attempt at a solution

    My question here is how am I supposed to answer this with the nearest tenth of a percent because of the answer.

    1500/1000 = 1.5
    1.5^(1/5) = 1.084471771
    1.084471771 – 1 = 0.084471771

    This could be 0.1

    1500/1000 = 1.5
    1.5^(1/60) = 1.006780637
    1.006780637 – 1 = 0.006780637

    Rounding to the nearest tenth of a percent would give you 0.0

    The answers just don't look "right" to me.
    Last edited: Oct 25, 2007
  2. jcsd
  3. Oct 25, 2007 #2


    User Avatar
    Science Advisor

    No. Remember that per cent means "per hundred" so a given percent corresponds to a decimal number equal to the percent divided by 100. To go from the percent to the number, multiply by 100. The decimal number is 0.084471771 which rounds, to the nearest 10th, to 0.1 but the percentage is 8.4471771% which rounds, to the nearest 10th percent, to 8.4%

    They shouldn't look right! That is 0.6780657% which is, to the nearest 10th percent, 0.7%.
  4. Oct 25, 2007 #3
    Blah, I see now. I left it in decimal form not as a percent. Thanks for the help!
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