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Math Help - interest problem

  1. #1
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    interest problem

    hello everyone. i hope this isn't too stupid a question or i didn't post it in the wrong section, i believe this is the right one based on the description.

    anyway, i am studying for a placement test and my math skills are pretty atrocious. on a study guide i am using i have come across an interest problem and i can't figure out how exactly to solve it.

    it's a word problem:
    Enrique put his money in the credit union for one year. His money earned 8% simple interest and at the end of the year his account was worth $1350. How much was originally invested?

    now here is where i will look truly pathetic. in the answer section of the study guide it gives me not only the answer to the problem but the equation used to solve it:

    $1250; x + 0. 08x = 1350

    the thing is, when i look at the equation x + .08x = 1350, i can't figure out how to solve it. i think it is the decimal that is throwing me off. i would appreciate if someone could break down exactly how to work a problem like this out on paper without using a calculator.
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  2. #2
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    Re: interest problem

    Quote Originally Posted by rainbowserpent View Post
    hello everyone. i hope this isn't too stupid a question or i didn't post it in the wrong section, i believe this is the right one based on the description.

    anyway, i am studying for a placement test and my math skills are pretty atrocious. on a study guide i am using i have come across an interest problem and i can't figure out how exactly to solve it.

    it's a word problem:
    Enrique put his money in the credit union for one year. His money earned 8% simple interest and at the end of the year his account was worth $1350. How much was originally invested?

    now here is where i will look truly pathetic. in the answer section of the study guide it gives me not only the answer to the problem but the equation used to solve it:

    $1250; x + 0. 08x = 1350

    the thing is, when i look at the equation x + .08x = 1350, i can't figure out how to solve it. i think it is the decimal that is throwing me off. i would appreciate if someone could break down exactly how to work a problem like this out on paper without using a calculator.
    Add the two terms on the left hand side. Then the next line is:

    1.08x = 1350 ....

    I would hope you know what to do next.
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  3. #3
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    Re: interest problem

    Quote Originally Posted by rainbowserpent View Post
    x + 0. 08x = 1350
    That means 1x + .08x; like 1 apple plus .08 apple = 1.08 apples.
    Remember that any variable by itself has an implied "1"; like v = 1v.
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  4. #4
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    Re: interest problem

    If your math skills are "atrocious" why are you trying so hard to pass a placement test at a higher level and avoid a class that would help you improve your class skills. You should want a score that accurately assses your ability, not one that is based on last minute prepping for specific questions.
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  5. #5
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    Re: interest problem

    Formula: Prt=I
    Principal * rate * time = Investment
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  6. #6
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    Re: interest problem

    Quote Originally Posted by theloser View Post
    Formula: Prt=I
    Principal * rate * time = Investment
    = Interest (not Investment)
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