In: Math
The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $170; the quantity demanded each month is 750 when the unit price is $150. The suppliers will market 750espresso makers if the unit price is $110. At a unit price of $130, they are willing to market 2250 units. Both the demand and supply equations are known to be linear.
(a) Find the demand equation.
p =
(b) Find the supply equation.
p =
(c) Find the equilibrium quantity and the equilibrium price.
| equilibrium quantity | units | |
| equilibrium price | $ | 
Given that,
The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $170;
the quantity demanded each month is 750 when the unit price is $150.
The suppliers will market 750espresso makers if the unit price is $110.
At a unit price of $130, they are willing to market 2250 units.
Both the supply and demand equations are linear.
The general equation of linear form is 
 ;
where m is slope
(a) Demand Equation :
Let the general equation be 
Here, x is the number of units ;
y is the price
So,
The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $170
That is, when x=250 ; y=$ 170
Substitute x=250 and y=$ 170 in 

Similarly, the quantity demanded each month is 750 when the unit price is $150.
That is , x=750 ; y=$ 150
Substitute in 

Subtracting 
 with 




So, slope is 
Substitute m in 




Substitute b and m in 

Therefore,
The demand curve is 
(b) Supply Curve:
Let the general equation be 
Here, x is the number of units ;
y is the price
So,
The suppliers will market 750espresso makers if the unit price is $110.
That is, when x=750 y=$ 110
Substitute x=750 and y=$110 in 

Similarly,At a unit price of $130, they are willing to market 2250 units.
That is, when x=2250 ; y=$ 130
Substitute x=2250 and y=$ 130 in 

Subtract 
 with 




So, substitute m=1/75 in 




Substitute b and m in 

Therefore,
The supply equation is 
(c) Equilibrium Quantity and Equilibrium Price:
Equilibrium occurs when demand is equal to supply

Equating both the suppply and demand equations
and 







Equilibrium Quantity = 1500
Substitute x=1500 in 



Equilibrium Quantity = 120
Therefore,
| Equilibrium Quantity | 1500 | Units | 
| Equilibrium Price | $ | 120 |