Question

alex is running in a clockwise direction around a circular track with radius 60 yards. he runs for 20 minutes at a speed of 4 yards per second. find the shortest distance between their starting point and their ending point measured along the track

Answer 1

Answer:

  100.9 yards

Step-by-step explanation:

One circuit of the track is a distance of ...

  C = 2πr = 2π(60 yd) = 120π yd.

At Alex's running rate, the distance covered in 20 minutes is ...

  (4 yd/s)(20 min)(60 s/min) = 4800 yd

The number of circuits will be ...

  (4800 yd)/(120π yd/circuit) = 40/π circuits ≈ 12.7324 circuits

The last of Alex's laps is more than half-completed, so the shortest distance to his starting point is 13 -12.7324 = 0.2676 circuits,

That distance is (0.2676 circuits)×(120π yd/circuit) ≈ 100.88 yd

The shortest distance along the track to Alex's starting point is about 100.9 yards.

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Additional comment

The exact distance is 120(13π-40) yards. The distance will vary according to your approximation for pi. If you use 3.14, this is about 98.4 yards.