How many pieces 9 in long can be cut from a 15 ft. piece of wood

7 1/4 = 7.25 

7.25 / 2 = 3.625 

So, I would think 3(C). 

3 x 2 = 6 

7.25 - 6 = 1.25 

So, it can't be 4. 

So, C must be the answer. 

I hope this helps! :)

The answer is that the rate of change is $50 per 1 monthhope this ; )