Christy drove 300 miles on her vacation. She drove 1.25 time faster on the second 150 miles of her trip than on the first. Which expression represents the time she spent driving? Let x be her speed for the fist half.
a. 375/x
b. 33.5/x
c. 270x
d. 270/x
1st half speed --- x
2nd half speed -- 1.25x
Since time = distance/rate
time for 1st part = 150/x
time for 2nd part = 150/1.25x
total time = 150/x + 150/1.25x
LCD = 1.25x
total time = (150(1.25) + 150)/1.25x
= 337.5/1.25x
= 270/x