A shopkeeper gives two successive discounts on an article marked ₹ 450. The first discount given is 10%. If the customer pays ₹ 344.25 for the article, the second discount given is (S.S.C., 2006)
Aptitude
Discount
Difficulty: Medium
Choose an option
-
A10%
-
B12%
-
C14%
-
D15%
Answer
Correct Answer: 15%
Explanation
### Concept & Successive Discounts
When two successive discounts are applied to a Marked Price ($MP$), the final Selling Price ($SP$) is calculated step-by-step. The first discount is applied to the $MP$, and the second discount is applied to the resulting discounted price.
$$SP = MP \times \left(1 - \frac{d_1}{100}\right) \times \left(1 - \frac{d_2}{100}\right)$$
### Step-by-Step Solution
* **Given:**
* Marked Price ($MP$) = ₹ $450$
* First Discount ($d_1$) = $10\%$
* Final Selling Price ($SP$) = ₹ $344.25$
* **Calculate price after first discount:**
* Discount amount = $10\%$ of $450 = 45$
* Price after 1st discount = $450 - 45 = 405$
* **Calculate the second discount:**
* The customer pays ₹ $344.25$ on the new price of ₹ $405$.
* Discount amount = $405 - 344.25 = 60.75$
* **Calculate the percentage of the second discount ($d_2$):**
* $d_2 = \left(\frac{60.75}{405}\right) \times 100$
* $d_2 = \frac{6075}{405} = 15\%$
### Exam Strategy & Shortcut
Work with multipliers for speed.
$450 \times 0.9 \times (1 - x) = 344.25$
$405 \times (1 - x) = 344.25$
$(1 - x) = \frac{344.25}{405} = 0.85$
This immediately tells you the multiplier is $0.85$, meaning the discount is $15\%$.
### Common Pitfall
A common error is calculating the second discount percentage on the original marked price (₹ $450$) instead of the intermediate discounted price (₹ $405$). Successive discounts must be applied sequentially.
### Final Answer
Therefore, the correct answer is **15%**.