The extra benefit gained from consumption of a good generally declines as extra units are consumed; this explains why the demand curve is downward sloping.
Marginal utility is the utility / satisfactiongained from the consumption of each additionalunit.
Total utility
Total utility is the overall benefit of consuming a good
The utility someone gains from consuming a good , informs their willingness to pay for it , so , if marginal utility was measured in money terms , the marginal utility curve becomes the persons demand curve .
As marginal utility decreases , the price a consumer would be willing to pay decreases , which explains why demand curve is downwards sloping
