Sadie ran for 3 miles/hour * 2 hour = <<3*2=6>>6 miles.
Ariana covered a distance of 6 miles/hour * (1/2) hour = 3 miles.
Sarah ran for 4.5 hours – 2 hours – 0.5 hours = <<4.5-2-0.5=2>>2 hours.
In this time, Sarah traveled a distance of 4 miles/hour * 2 hours = <<4*2=8>>8 miles.
The total distance for the race was 6 miles + 3 miles + 8 miles = <<6+3+8=17>>17 miles.
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