Explanation: To understand the concept of successive discounts, let's break down the problem step by step.
The printed price of the calculator is Rs 200. The retailer pays Rs 153 after receiving two successive discounts: the first is 10%, and the second is an unknown rate.
First, we apply the 10% discount to the printed price:
\[ \text{Price after first discount} = 200 - (10\% \times 200) = 200 - 20 = 180 \]
Next, we need to find the second discount rate that reduces the price from Rs 180 to Rs 153. Let the second discount rate be \( x \% \).
The price after the second discount is:
\[ \text{Price after second discount} = 180 - (x\% \times 180) = 153 \]
We can set up the equation:
\[ 180 - \left(\frac{x}{100} \times 180\right) = 153 \]
Solving for \( x \):
\[ 180 - 1.8x = 153 \]
\[ 1.8x = 180 - 153 \]
\[ 1.8x = 27 \]
\[ x = \frac{27}{1.8} \]
\[ x = 15 \]
Thus, the second discount rate is 15%.
This problem demonstrates the application of successive discounts, where each discount is applied to the reduced price after the previous discount. It is crucial to apply each discount step by step and not to the original price. Understanding this concept is essential for solving similar problems involving multiple discounts in competitive examinations and real-world scenarios.