Answer:
A
Step-by-step explanation:
When you read the question it says that her average speed from the library to the gym is 15 mph less than her speed from her home to the library. So x - 15 is what describes that situation.
If it is A it cannot be anything else.
B is incorrect. x - 15 is not a time. It is a rate. It can be used to develop the amount of time, but by itself it is still A.
C is incorrect. Her average speed from her house to the library is x
D is incorrect. The distance is given as the same as from her home to the library as from the library to the gym. Both are 4
