Question

Katalin drove 180 miles on her vacation. She drove an average of 1.5 times faster on the second 90 miles of her trip than she did on the first 90 miles of her trip. Which expression represents the time she spent driving? Let x = her speed on the first half of the trip.

Answer 1

Answer: 150/x

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Work Shown:

x = speed on 1st half of the trip

distance = rate*time

90 = x*t

t = 90/x

She spent 90/x hours driving on the 1st half of the trip

1.5x = speed on the 2nd half of the trip

d = r*t

t = d/r

t = 90/(1.5x)

t = 60/x

She spent 60/x hours driving on the 2nd half of the trip

Overall, she spent 90/x+60/x hours driving the entire 180 mile trip.

Edit:

That expression simplifies to 150/x since 90+60 = 150