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Guided, difficulty 2 of 3

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A regulator wants to estimate the share of small businesses that use electronic invoicing with a 95% margin of error of at most ±3.0 percentage points. With no prior idea of the share, it plans for the worst case $\hat{p} = 0.5$ . Solve $1.96\sqrt{0.5 \times 0.5 / n} \le 0.030$ for $n$ , and give the smallest whole number of businesses needed.