In Exercises 40 through 49, assume that the required extreme value is a relative extremum.

In a learning experiment, a subject is first given x minutes to examine a list of facts. The fact sheet is then taken away and the subject is allowed y minutes to prepare mentally for an exam based on the fact sheet. Suppose it is found that the score achieved by a particular subject is related to x and y by the formula

a. What score does the subject achieve if he takes the test “cold” (with no study or contemplation)?

b. How much time should the subject spend in study and contemplation to maximize his score? What is the maximum score?

Transcribed Image Text:

S(x, y) = x² + xy + 10x - y² + y + 15