Three successive discounts of 30% on the marked price of an item are together equivalent to a single discount of:

Three successive discounts of 30%.

Discount =$$\text{ Marked Price} \times \frac{ 100 - Discount}{100}$$​​

Let the Marked Price be 100.

then, $$100 \times \frac{70}{100}\times \frac{70}{100}\times \frac {70}{100} = 34.3\%$$

Discount,

 100 - 34.3% = 65.7 %   

Total Discount = $$\frac{1000-343}{1000}\times 100 = 65.7\%$$​

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