Finding the Equilibrium Price and Quantity for a Simple Linear Equation?

[vitaminZ]

Homework Statement

P = -50Qd + 80
P = 2Qs + 10

P = Price
Qd = Quantity demanded
Qs = Quantity supplied

Find the equilibrium Price and Quantity.

Homework Equations

Qd = Qs
(equilibrium)

The Attempt at a Solution

Qd = Qs
Q

Since they both equal to P

-50Q + 80 = 2Q + 10 [-2Q]
-52Q + 80 = 10 [-80]
-52Q = -70 [/52Q]
Q = 70/52
Equilibrium Quantity = 70/52

I don't know why this is wrong?

 

[TxRationalist]

I came up with the same answer. I didn't major in economics, though...I just assumed (because it sounds right) that you are right, that equilibrium occurs when the supply = demand.

 

[Mark44]

Are you sure that you are starting with the right equations? Have you given the problem exactly as it appears in your text or wherever you got it? I'm especially concerned with your Qd equation with the -50 coefficient.

 

[utkarsh009]

Homework Statement

P = 2Qs + 10

are you sure that this equation has 2Qs or should it have 20Qs.