D(Pcoke)= 26.17 - 3.98Pcoke + 2,25Ppepsi + 1.10acoke-0.62apepsi + 9.58s + 0.99Y where: aj is advertising expenses = $110, s=1 if summer, s=0 otherwise y is real income=$200, Pcoke =$1 and Ppepsi = $3

What is the quantity demanded for coke in the summer? Is coke a normal good or an inferior good? Is coke a elastic or inelastic good? explain how the equation led you to your answer)? Calculate the cross price elasticity of demand for coke and Pepsi and explain the nature of the result?