The second new species named Puntius euspilurus is an edible freshwater fish found in the Mananthavady river in Wayanad. It appears in great numbers in paddy fields during the onset of the Southwest monsoon.

Supply schedule (linear relationship between price and quantity supplie

Question

The second new species named Puntius euspilurus is an edible freshwater fish found in the Mananthavady river in Wayanad. It appears in great numbers in paddy fields during the onset of the Southwest monsoon.

Supply schedule (linear relationship between price and quantity supplied):

| Price P per kg (in ₹) | Quantity (X) of Fish Supplied (in kg) |
|---|---|
| 25 | 800 |
| 20 | 700 |
| 15 | 600 |
| 10 | 500 |
| 5 | 400 |

Kerala demand schedule (linear relationship between price and quantity demanded):

| Price (p) per kg (in ₹) | Quantity (x) of Fish Demanded (in kg) |
|---|---|
| 25 | 200 |
| 20 | 400 |
| 15 | 600 |
| 10 | 800 |
| 5 | 1000 |

The equation of demand curve can be given by
(a) $p = 30 - \frac{x}{40}$
(b) $p = 30 + \frac{x}{40}$
(c) $p = 20 - \frac{x}{40}$
(d) $p = 20 + \frac{x}{40}$

Accepted Answer

> [!TLDR]
> The demand data are linear with negative slope $-	frac{1}{40}$ and intercept $30$, giving $p=30-	frac{x}{40}$ — option (a).

> [!FORMULA]
> **Linear relation:** $p=a+bx$, $b=\dfrac{\Delta p}{\Delta x}$.

| Price $p$ (₹) | Demand $x$ (kg) |
|---|---|
| 25 | 200 |
| 20 | 400 |
| 15 | 600 |
| 10 | 800 |
| 5 | 1000 |

1. As $x$ rises by $200$, $p$ falls by $5$, so $b=\dfrac{-5}{200}=-\dfrac{1}{40}$ (negative — demand).
2. Model $p=a-\dfrac{x}{40}$; use $(x,p)=(200,25)$: $25=a-\dfrac{200}{40}=a-5$.
3. $a=30$.
4. Hence $p=30-\dfrac{x}{40}$; check $(1000,5)$: $30-	frac{1000}{40}=30-25=5$ ✓.

> [!ANSWER]
> Option **(a)** $p=30-\dfrac{x}{40}$.

Type	What it shows	Who it's for
Individual Supply Schedule	One seller's quantities at various prices	A single firm
Market Supply Schedule	Total quantities from all sellers at various prices	The entire market

Concept understanding — Supply Schedule

Supply Schedule: From Intuition to Definition

The Precise Statement

A Concrete Example

Why This Matters

Price (₹ per glass)	Quantity Supplied (glasses per day)
5	10
10	50
15	80
20	100

🎓Unlock everything free for 14 days

Unlock everything free for 14 days