Average Acceleration and Speed

[OverlordXero]

Homework Statement

You are driving down a highway at a speed of 25.0 mph when your car accelerates at 55 mph in order to pass another car. What is the average acceleration of this car if this increase in speed occurs over a time period of 5.00 seconds?

t = 5 seconds
initial speed = 25.0 mph
acceleration = 55 mph

Homework Equations

a = delta v/ t

The Attempt at a Solution

55+(5/3600)-25 /5
=0.0176 mph

the answer is 6.00 mph/s but i still don't understand how to solve for it

 

[andrewkirk]

The problem is incorrectly stated. One accelerates to 55mph, not at 55mph. 55mph cannot be an acceleration as it is in the wrong units. From the context, it is clear that it is intended to be the final speed.