A farmer has 80 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 rectangular sheet of cardboard 18 cm × 48 cm by cutting equal squares of side x from the four corners and folding up the sides. Find the largest possible volume V.
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 radius r that uses the least material.
An open box (no lid) with a square base must hold 62500 cm³. Use the least possible material, that is the smallest area of the base plus the four sides. Find the minimum surface area S.
A small firm sells its product at a fixed market price of €65 per unit. Producing q units costs C(q) = 100 + 48q + 0.2q² euros. Find the maximum profit P.
A small firm sells its product at a fixed market price of €50 per unit. Producing q units costs C(q) = 5300 + 4q + 0.02q² euros. Find the maximum profit P.
Answer key
- 1. A = 800 m²
- 2. V = 1600 cm³
- 3. r = 3.993 cm
- 4. S = 7500 cm²
- 5. P = 261.3 €
- 6. P = 21150 €
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