Let Qd = 10 p + r represent the demand for raincoats in Seattle, where r is the monthly average rain level. Let Qs = p- r represent the supply for the raincoat. 3. Calculate the effect of a small increase in rain level on raincoat price. 4. Assume rain is a wind (w) function as r = w. Find the effect of a small increase in wind level on raincoat price.