SOLUTION: Elizabeth drove the first half of a trip at 36 mi/h. At what speed should she cover the remaining half in order to average 45 mi/h for the whole trip?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Elizabeth drove the first half of a trip at 36 mi/h. At what speed should she cover the remaining half in order to average 45 mi/h for the whole trip?      Log On


   

Question 72140This question is from textbook Algebra and Trigonometry: Structure and Method
: Elizabeth drove the first half of a trip at 36 mi/h. At what speed should she cover the remaining half in order to average 45 mi/h for the whole trip? This question is from textbook Algebra and Trigonometry: Structure and Method

Answer by checkley75(3666) About Me  (Show Source):
You can put this solution on YOUR website!
36/2+X/2=45
36/2+X/2=45
(36+X)/2=45
90=36+X
X=90-36
X=54 MPH FOR THE LAST HALF OF THE TRIP.
PROOF
36/2+54/2=45
18+27=45
45=45