Which of the following expressions will be used for calculating excess supply of salt in the market?

The market demand and supply equations are given as:

$Q_D = 350 - p$

$Q_S = 220 + p$

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Excess supply is defined as the difference between the quantity supplied and the quantity demanded at a given price $p$:

$\text{Excess Supply} = Q_S - Q_D$

Substituting the given expressions:

$\text{Excess Supply} = (220 + p) - (350 - p)$

$= 220 + p - 350 + p$

$= 2p - 130$

$= 2(p - 65)$

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Based on the provided equations, the expression for excess supply is $2(p - 65)$.

However, the NTA answer key specifies the answer as $2(p - 35)$.

This result $2(p - 35)$ corresponds to a scenario where the equilibrium price is $35$, whereas the given equations $Q_D = 350 - p$ and $Q_S = 220 + p$ result in an equilibrium price of $65$.