An open box is made from a rectangular sheet of cardboard 15 cm × 24 cm by cutting equal squares of side x from the four corners and folding up the sides. Find the cut x that gives the largest volume.
Optimization worksheet with answers
A rectangular pen is fenced with 120 m of fencing and divided into two parts by one extra fence parallel to the sides of length x (three fences of length x and two of length y in total). Find the largest total area A that can be enclosed.
A closed cylindrical can (with a top and a bottom) must hold 1000 cm³. The metal used is proportional to the total surface area. Find the radius r that uses the least material.
A closed cylindrical can (with a top and a bottom) must hold 1000 cm³. The metal used is proportional to the total surface area. Find the height h of the can that uses the least material.
A company sells q units per week. The price at which it can sell them is p = 90 − 1q euros per unit, and the cost is C(q) = 500 + 35q euros. Find the maximum weekly profit P.
A company sells q units per week. The price at which it can sell them is p = 160 − 0.5q euros per unit, and the cost is C(q) = 3600 + 40q euros. Find the maximum weekly profit P.
Answer key
- 1. x = 3 cm
- 2. A = 600 m²
- 3. r = 5.419 cm
- 4. h = 10.84 cm
- 5. P = 256.3 €
- 6. P = 3600 €
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