a maths questions, is it maxima and minima?

Question

I start from point A and can transport 15 containers in my car to point c. Each container will sell at 25 rupees at point C. I stop at pointB where I can deliver max 7 containers, here each container sells at 20 rupees. Also I can take some containers from point B and sell at point C, these containers sell at point c at 10 rupees.

Now I need to maximize my profit. How do I solve it?

Answer 1

if you dont have any transport cost, you want to sell as many as you can at B 7 @ 20, and as many as you could carry with them at C = 8@10

Answer 2

Sell 7 containers at point B getting 7*20 = 140 rupees
Get 7 containers and selat point C for 7*10 =70 rupes
Sell 8 containers at point C for 8*25 = 200 rupees
Total = 410 rupees.

All other combinations are less than 410.