Answer: 4 hours, 41 minutes
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Explanation:
point A = Brianna's college
point B = Brianna's home
d = distance from A to B
Going from A to B, she travels a distance d and has speed r = 62.4
d = r*t
d = 62.4*t
t = d/62.4
represents the time it takes to go from A to B.
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The time it takes to go from B to A is t = d/57.4 because her speed is now 57.4 mph
The total time is 9 hours, so,
(time going from A to B) + (time from B to A) = 9
(d/62.4) + (d/57.4) = 9
62.4*57.4 * ( d/62.4 + d/57.4 ) = 62.4*57.4 *9
57.4d + 62.4d = 32235.84
119.8d = 32235.84
d = 32235.84/119.8
d = 269.080467445742
d = 269.0805
The distance from Brianna's home to her college is approximately 269.0805 miles
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Time it takes going from B to A = d/57.4 = 269.0805/57.4 = 4.6878
It takes about 4.6878 hours to go from her home back to the college.
Convert from hours to hours+minutes
4.6878 hours = 4 hours + 0.6878 hours
4.6878 hours = 4 hours + (0.6878 hours)*(60 min/1 hr)
4.6878 hours = 4 hours + 41.268 minutes
4.6878 hours = 4 hours + 41 minutes ... rounding to the nearest minute
4.6878 hours = 4 hours, 41 minutes
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side note:
4 hrs, 41 min = 4*60 + 41 = 240+41 = 281 minutes
