Airplanes can reduce their noise by flying slower and incurring extra costs. There are two types of airplane, Airbus and Boeing. If an Airbus produces QA noise, its private marginal benefit from producing extra noise is = 10 .01 ($/decibel). If a Boeing produces QB noise, its private marginal benefit of extra noise is = 20 .02 ($/decibel). Both of these Private Marginal Benefit Schedules are drawn on the attached Curve Sheet A