Christy drove 300 miles on her vacation. She drove an average of 1.25 times faster on the second 150 miles of her trip. Which expression represents the time she spent driving? Let x= her speed on the first half of the trip.
a.375/x
b. 337.5/x
c.270x
d. 270/x

Question

Christy drove 300 miles on her vacation. She drove an average of 1.25 times faster on the second 150 miles of her trip. Which expression represents the time she spent driving? Let x= her speed on the first half of the trip.
a.375/x
b. 337.5/x
c.270x
d. 270/x

mathstudent55 · Answer

speed = distance/time
time = distance/speed

mathstudent55 · Answer

speed in first half: x
speed in second half: 1.25x
distance in first half: 150 miles
distance in second half: 150 miles
Use the second formula above for each half, and add them.