



 
Hi Asher, Suppose the question was What percent of 12 is 3? The answer would be \[\frac{3}{12} \times 100 = 25\] so 3 is 25% of 12. But the question is What percent of 0 is 1? Following the same procedure the answer is \[\frac{1}{0} \times 100.\] But division by zero is not a permissible operation so this expression is meaningless. There is no numerical answer to the question What percent of 0 is 1? For your question about profit suppose you purchased an item for $\$9$ and you sold it for $\$12.$ Your profit is them $\$12  \$9 = \$3.$ Profit, expressed as a percent is the profit as a percentage of the selling price. Hence in this case the profit is \[\frac{\$3}{\$12} \times 100 = 25 \mbox{ or 25%.}\] Hence if you purchased something for 0 dollar and sold it for 1 dollar you profit would be 100%. I hope this helps, 



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