Q: The task is to generate the correct answer for a given math problem.
Problem: the speed of a subway train is represented by the equation z = s ^ 2 + 2 s for all situations where 0 s 7 , where z is the rate of speed in kilometers per hour and s is the time in seconds from the moment the train starts moving . in kilometers per hour , how much faster is the subway train moving after 7 seconds than it was moving after 5 seconds ?
A:
28