A farmer encloses a rectangular field against a straight stone wall (using the wall as one side) with 120 meters of fencing. What is the maximum possible area of the field?
Answer and explanation
Correct answer: A.
**Answer: . Why not the others:** assumes a square with all 4 sides fenced (); is ; uses .
- Step 1: Let be the width perpendicular to the wall. The two widths and one length sum to , so .
- Step 2: The area function is . Setting . The length is . Maximum area is .
Practise more Differential and Integral Calculus, Differential Equations, and Probability.
Free questions with an explanation for every one, and full timed CESS & Examen d'entrée (Belgium) mock tests.