Solution 1

Given:

WTA = 100 + 5*Q

P = 250

Start by finding the quantity he will sell:

WTA = P

100 + 5*Q = 250

5*Q = 150

Q = 30

Drawing the PS diagram:

Calculating the area of the triangle:

PS = (1/2)*30*(250-100)

PS = (1/2)*30*150

PS = 2,250