Question

When p = $5, the quantity demanded of a good is 30 units, and the quantity supplied of the good is 50 units. For every $1 decrease in the price of this good, quantity demanded rises by 5 units and quantity supplied falls by 5 units. The equilibrium price of this good is ___________and the equilibrium quantity of this good is _________ units?

Answer 1

Answer: Equilibrium price is $3 and equilibrium quantity is 40 units.

Explanation:

Demand equation is given by,

$Qd= a-bP When P= 5, Qd=30 30 = a – 5b Change in Quantity demanded = Change in a – (b Change in P) 5 = 0 – b(-1) b=5 So, a = 55$

Therefore the demand equation is given by, $Qd= 55 – 5P$

Supply equation is given by

$Qs= c + dP When P= 5, Qs = 50 50 = c + 5d Change in Quantity supplied = Change in c + d(Change in P) -5 = 0 + d(-1) d=5 So, c=25$

Therefore, the supply equation is given by,  

$Qs= 25 + 5P$

Equilibrium is given by

$Qd=Qs 55 – 5P= 25 + 5P 30=10P P= 3 And Equilibrium quantity is, Q= 55 – 5(3) = 55 – 15 = 40 units.$