Assume the demand for good X is log linear, with QX = c / (PX)^1/2. (a) If the quantity demanded is 120 when PX is $2.00, what is the quantity demanded when PX rises to $4.50? HINT: Begin by finding the value of the constant c. (b) Using your answer in part (a), find the precise arc price elasticity between $2.00 and $4.50.