First, we need to find the cost per bottle for both offers:
3 / 24 = 0.125$
4 / 36 = 0.11$
(Note: I divided 3 by 24 bc we are spreading the 3 dollars over 24 bottles. If I wanted to find the number of bottles per bottle, I would divide 24 by 3.)
The cheaper per bottle offer is 36 bottles for 4$. The only option for this is D. We can calculate the difference by subtracting 0.11 from 0.125, which is 0.014$ or 1.4¢. Hope that helps!