An economist believes there is a linear relationship between the market price of a particular commodity and the number of units suppliers of the commodity are willing to bring to the marketplace. Two...

An economist believes there is a linear relationship between the market
price of a particular commodity and the number of units suppliers of the
commodity are willing to bring to the marketplace. Two sample
observations indicate that when the price equals $15 per unit, the weekly supply equals 30,000 units; and when the price equals $20 per unit, the
weekly supply equals 48,000 units

(i) If price per unit, p, is plotted on the horizontal axis and the quantity
supplied q is plotted on the vertical axis, determine the slope-intercept form
of the equation of the line which passes through these two points.
(ii) Interpret the slope of the equation in this application.
(iii) Predict the weekly supply if the market price equals $25 per unit.