Jasmine allows 4% discount on the marked price of her goods and still earns a profit of 20%. What is the cost price of a shirt if its marked price is 850?
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The direct formula \( \text{CP} = \text{MP} \times \frac{100 - \text{Discount \%}}{100 + \text{Profit \%}} \) is very efficient for problems relating Cost Price, Marked Price, Discount, and Profit. Ensure to correctly substitute percentages.