Q1.
What happens when you consume the first mango? It tastes delicious, right? The second one is good? The third one and so on? You are barely interested in eating mangoes by this point. Why do you think this happens?
Answer
Because the extra satisfaction you get from each additional mango is smaller than from the one before — the principle of diminishing marginal utility. The mango has not changed; your hunger for it has.
1st mango → utility very high (you were hungry for it)
2nd mango → still good, but less than the first
3rd mango → only mildly enjoyable
4th mango → almost no extra satisfaction
Additional utility falls as more of the same good is consumed
2nd mango → still good, but less than the first
3rd mango → only mildly enjoyable
4th mango → almost no extra satisfaction
Additional utility falls as more of the same good is consumed
And this is exactly why the demand curve slopes downward, which is the reason the box is placed in this section. If the fourth mango gives you far less satisfaction than the first, you will not pay the same price for it. As the chapter puts it: “As the utility derived from a successive quantity of products falls, the willingness to pay for the products also decreases, so demand falls.”
Look again at Srivalli's schedule with this in mind:
| Kilogram | Highest price she will pay for it | Why |
|---|---|---|
| 1st kg | ₹150 | The first mangoes of the season — worth a lot to her |
| 2nd kg | ₹100 | Welcome, but she already has mangoes at home |
| 3rd kg | ₹50 | Only worth buying if they are cheap |
Why it must be so: if every extra unit gave the same satisfaction as the first, a person would keep buying the good forever at any price, and demand curves would be flat lines. The falling satisfaction is what makes a buyer say “only at a lower price” — and that sentence, repeated by every buyer, is the downward-sloping demand curve.
Try this: the principle is not about mangoes. Try it with glasses of water on a hot afternoon, or with a second and third helping of a favourite dish. The first is precious, the fourth is a burden — and you would not pay the same for both.