Q. The difference between a single discount of 30% on 550 Rs. and two successive discounts of 20% and 10% on the same amount is :
Answer: 11 Rs.
Notes: Case I : A single discount of 30% Case II : Two successive discounts of 20% and 10% Single equivalent discount $latex = \left ( 20+10-\frac{20\times 10}{100} \right )\% = 28\%&s=1$ Difference $latex = \left ( 30 - 28 \right )\% = 2\%$ ∴ Required Difference = 2% of 550 $latex = \frac{2\times 550}{100} = 11\ Rs.&s=1$ Hence option [B] is correct answer.

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