=+12.7 Everyday Application: To Study or to Sleep?: Research suggests that successful performance on exams requires preparation (that is, studying) and rest (that is, sleep). Neither by itself produces good exam grades, but in the right combination they maximize exam performance.

A. We can then model exam grades as emerging from a production process that takes hours of studying and hours of sleep as inputs. Suppose this production process is homothetic and has decreasing returns to scale.