Larry Mitchell invested part of his $31,000 advance at 6% annual simple interest and the rest at 7%

Discussion in 'Calculator Requests' started by math_celebrity, Feb 1, 2017.

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  1. math_celebrity

    math_celebrity Administrator Staff Member

    Larry Mitchell invested part of his $31,000 advance at 6% annual simple interest and the rest at 7% annual simple interest. If the total yearly interest from both accounts was $2,090, find the amount invested at each rate.

    Let x be the amount invested at 6%. Then 31000 - x is invested at 7%.

    We have the following equation:
    0.06x + (31000 - x)0.07 = 2090

    Simplify:
    0.06x + 2170 - 0.07x = 2090

    Combine like Terms
    -0.01x + 2170 = 2090

    Subtract 2170 from each side
    -0.01x = -80

    Divide each side by -0.01
    x = 8000 at 6%

    Which means at 7%, we have:
    31000 - 8000 = 23,000
     

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