Answer:
-130.8
Step-by-step explanation:
The average of the two slope values is ...
(-148.8 -112.8)/2 = -261.6/2 = -130.8
The slope of the tangent line at t=15 is approximately -130.8.
The correct answer is c. There is no possible way to know how much the mean age decreases, but we know it definitely will (averages decrease as values less than the average are added to the data.) <span />