$3.75 in quarters and nickles in her car. The number of nickles is fifteen more than the number of q

Discussion in 'Calculator Requests' started by math_celebrity, Sep 15, 2019.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    $3.75 in quarters and nickels in her car. The number of nickels is fifteen more than the number of quarters. How many of each type of coin does she have?

    Let the number of nickels be n, and the number of quarters be q. We know nickels are 0.05, and quarters are 0.25. We're given:
    1. n = q + 15
    2. 0.05n + 0.25q = 3.75
    Substituting (1) into (2), we get:
    0.05(q + 15) + 0.25q = 3.75
    0.05q + 0.75 + 0.25q = 3.75

    Combine like term:
    0.3q + 0.75 = 3.75

    Typing this equation into our calculator, we get:
    q = 10

    Substituting q = 10 into Equation (1), we get:
    n = 10 + 15
    n = 25
     

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