Problema Solution
Mary competed in a biathlon that involved running and cycling. She covered a total distance of 65 miles in 3 hours. If she ran at a rate of 5 mph and cycled at a rate of 25 mph, how long did she spend running
Answer provided by our tutors
Let
t = the time Mary spent running
3 - t = the time Mary spent cycling
v1 = 5 mph the running rate
v2 = 25 mph the cycling rate
d = 65 mi the total distances Mary passed
Since distance = speed*time we have:
v1*t + v2*(3 - t) = d
5t + 25(3 - t) = 65
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click here to see the equation solved for t
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t = 0.5 hr
t = 0.5*60 min
t = 30 min
Mary spent 30 minutes running.