Question 645232
For the first 5 miles of a 10-mile race, Joshua's rate was 10 mph. for the last 5 miles, his rte slowed to 8 mph. How long it take for Joshua to complete the race?
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His avg speed for the 10 miles = 2*10*8/(10+8) = 80/9 mi/hr
d = r*t
t = d/r = 10/(80/9) = 9/8
t = 1.125 hours