Answer: 15 miles
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Work Shown:
t = time it takes to go from Jackie's house to her friends house
distance = rate*time
d = 30*t
This represents the distance they travel if they go 30 mph
Then when going back home, they take 6 minutes longer
6 minutes = 6/60 = 0.1 hours
So they take 0.1 hours longer meaning the t updates to t+0.1
d = r*t
d = 25*(t+0.1)
d = 25t+2.5
This represents the trip back home.
Since the distance d doesn't change, we can equate the two right hand sides and solve for t
30t = 25t+2.5
30t-25t = 2.5
5t = 2.5
t = 2.5/5
t = 0.5 hours = 30 minutes
d = 30t = 30*0.5 = 15 miles