Question

Brianna drove home from college traveling an average speed of 62.4 mph and drove back to the

Answer 1

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