Algebra Distance Problem Help?

The speed of a moving walkway is 2.6 feet per second. It takes Kim a total of 50 seconds to travel 65 feet with the movement of the walkway, and back, with the movement against the walkway. What is Kim's normal walking speed???

I understand the basics of this question, and the t=s/v However, something goes wrong for me when I get to the quadratic formula portion of the equation. Can someone please give a detailed answer? THANKS!

Update:

Awesome! I appreciate the help - thanks so much! :)

Comments

  • n = normal walking speed

    t = time walking with walkway

    50 - t = time against

    65 = (n + 2.6) • t

    65 = (n - 2.6) (50 - t)

    From the first, 65/(n + 2.6) =t

    So that makes the second be 65 = (n - 2.6)[50 - 65/(n + 2.6)]

    FOIL it out

    65 = 50n - 65n/(n + 2.6) - 130 + 169/(n + 2.6)

    Multiply by (n + 2.6)

    65(n + 2.6) = 50n(n + 2.6) - 65n - 130(n + 2.6) + 169

    65n + 169 = 50n^2 + 130n - 65n - 130n - 338 + 169

    0 = 50n^2 + 130n - 65n - 130n - 338 + 169 - 65n - 169

    0 = 50n^2 - 130n - 338

    0 = 25n^2 - 65n - 169

    so by the QF, n = 65 + √(4225 - 4(25)(-169)) over 2(25)

    n = (65 + 145.3444)÷50

    n is about 4.21 ft/sec

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