A farmer has 40 m of fencing to enclose a rectangular field along a straight river. No fence is needed along the river. Find the largest area A that can be enclosed.
Optimization worksheet with answers
An open box is made from a square sheet of cardboard 48 cm × 48 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.
A closed cylindrical can (with a top and a bottom) must hold 400 cm³. The metal used is proportional to the total surface area. Find the smallest possible surface area A.
A closed cylindrical can (with a top and a bottom) must hold 250 cm³. The metal used is proportional to the total surface area. Find the smallest possible surface area A.
A company sells q units per week. The price at which it can sell them is p = 140 − 1q euros per unit, and the cost is C(q) = 1500 + 30q euros. Find the maximum weekly profit P.
A company sells q units per week. The price at which it can sell them is p = 170 − 1q euros per unit, and the cost is C(q) = 700 + 50q euros. Find the price p that maximises profit.
Answer key
- 1. A = 200 m²
- 2. x = 8 cm
- 3. A = 300.5 cm²
- 4. A = 219.7 cm²
- 5. P = 1525 €
- 6. p = 110 €
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