When the price is 0 the quantity demanded is 500, and when the price changes by 10 the quantity would change in 100 units. Then what’s the unit price elasticity when the price is 20 a. -1.5
b. -0.5
c. +0.25
d. 5

44

step-by-step explanation:

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)

just sum

10 + 10 = 20