Imagine a popular ice‑cream stand on a hot day.
Demand (how many people want ice‑cream) is higher than Supply (how many cones the stand can make).
The result is a shortage – people are left waiting, and the price tends to rise.
Now picture a bakery that has baked 200 loaves of bread, but only 150 people come in.
The bakery has a surplus – more goods than customers.
The price usually falls to attract more buyers.
In a simple market we can write the demand and supply equations as:
Where \$P\$ is price, \$Q\$ is quantity, and \$a, b, c, d\$ are constants.
When \$Qd = Qs\$, the market is in equilibrium.
The equilibrium price \$P^*\$ and quantity \$Q^*\$ can be found by solving:
\$ a - bP^* = c + dP^* \$
\$ P^* = \frac{a - c}{b + d} \$
\$ Q^* = a - bP^* \$
| Price ($) | Quantity Demanded | Quantity Supplied | Result |
|---|---|---|---|
| 5 | 120 | 80 | Shortage 📉 |
| 10 | 70 | 110 | Surplus 📈 |
When you see a diagram or data table, first check whether the quantity demanded is higher or lower than the quantity supplied at the given price.
Remember: Price is the signal that moves the market back towards equilibrium.
Think of a classroom where the teacher (price) decides how many students (buyers) can sit at each desk (goods).
If too many students try to sit (high demand) but there are not enough desks (low supply), the teacher raises the “seat price” – maybe by asking for extra homework – to reduce the number of students.
If there are many empty desks (high supply) but few students, the teacher lowers the “seat price” to attract more students.