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2011 AMC 10B Problem 12

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2011 AMC 10B Problem 12AMC 10 Step by Step
Name:                             Date: September 13, 2026
Circles · difficulty 2 of 5 · about 3 min · position P11-15

Keiko walks once around a track at exactly the same constant speed every day. The sides of the track are straight, and the ends are semicircles. The track has a width of 66 meters, and it takes her 3636 seconds longer to walk around the outside edge of the track than around the inside edge. What is Keiko's speed in meters per second?

  1. A)

    π3\frac{\pi}{3}

  2. B)

    2π3\frac{2\pi}{3}

  3. C)

    π\pi

  4. D)

    4π3\frac{4\pi}{3}

  5. E)

    5π3\frac{5\pi}{3}

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