Excuse me but his answer is incorrect. To find the proper rate of change you might have to solve it like you would for slope. First you would find the points for x = 3 and x = 15 would be (3, 0.08) and (15, 327.68). Then using the slope formula you can find 327.60/ 12. That gives 27.3. So in that case the correct answer is C.
328÷172 how many times can 328 go into 172 so u have to multiply 172 by 2 if it goes over then put on top of the one and then subtract 328 by 172 and u got ur answer and remaining