## Precalculus (10th Edition)

At least $300$.
The equation according to the question, because the average daily cost must be not greater than $100$: $\overline{C}(x)\leq100\\\frac{80x+6000}{x}\leq100\\80x+6000\leq100x\\6000<20x\\300\leq x$ Hence at least $300$ bicycles must be produced.