erin drove home at an average speed of 45 mph she returned h

erin drove home at an average speed of 45 mph. she returned home in the evening along the same route and average 30 mph. if erin spent a total of 1 hour commuting to and from work, how many miles did erin drive to work in the morning?

Solution

erin drove home at an average speed of 45 mph.
DATA:
rate = 45 mph ; distance = x miles ; time = x/45 hrs
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she returned home in the evening along the same route and average 30 mph.
DATA:
rate = 30 mph ; distance = x miles ; time = x/30 hrs
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if erin spent a total of 1 hour commuting to and from work, how many miles did erin drive to work in the morning?
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Equation:
time to + time from = 1 hr
x/45 + x/30 = 1
(30x + 45x) = 30*45
75x = 1350
x = 18 miles (distance to work in the morning)