Kevin and randy have a jar containing 41 coins, all of which are either quarters or nickels. The tot

Discussion in 'Calculator Requests' started by math_celebrity, Oct 30, 2016.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Kevin and randy have a jar containing 41 coins, all of which are either quarters or nickels. The total value of the jar is $7.85. How many of each type?

    Let d be dimes and q be quarters. Set up two equations from our givens:
    1. d + q = 41
    2. 0.1d + 0.25q = 7.85
    Rearrange (1) by subtracting q from each side:
    (3) d = 41 - q

    Now, substitute (3) into (2)
    0.1(41 - q) + 0.25q = 7.85
    4.1 - 0.1q + 0.25q = 7.85

    Combine q terms
    0.15q + 4.1 = 7.85

    Using our equation calculator, we get:
    q = 25

    Substitute q = 25 into (3)
    d = 41 - 25
    d = 16
     

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