A spring is being stretched by a weight d(t)=100t/2t+15
, where d is measured in centimeters and t is in seconds.

Find the average rate of change on the interval (20, 25).
___ cm/sec

Find the average rate of change on the interval (24, 25).
___ cm/sec

Find the average rate of change on the interval (24.9, 25).
___ cm/sec