With a lot of people in one place, it more difficult for Arlette to see the older woman and notice her problem. She probably only looks at what is in front of her eyes and in her way, not the sides if she is in a hurry or entertained with something. The noise who emit the people blocks the sound of the pain of the old lady.
The change in total benefit that has comes from an action is the : Marginal benefit As we consume more of the same product, the marginal benefit and satisfaction of consuming that product will become less and less
