What is the answer. Please explain

Question

Select the situation in which one quantity is changing at a constant rate in relation to another quantity.
a. Emma read 15 pages of her novel each hour.
b. The production of wool at a factory doubles every 2 years.
c. Claire earns 2% interest on her retirement fund every month.
d.The value of a car is 0.8 times the value of the car the previous year.

Answer 1

(a) because the number of pages read with respect to time is a constant 15 pages per hour.

 

 

This is the only answer that has a constant rate of change.  Both (b) and (c) have increasing rates of change, while (d) has a decreasing rate of change.

 

 

Answer 2

The rate of change compares two quantities that are changing. 

rate of change = change in the dependent variable

                            change in the independent variable

 

(a) expresses this concept: 15 pages/1 hour