Question

The list price of a watch is Rs.400. A customer gets two successive discounts, the first being 10%. Calculate, in percentage, the second discount, if the customer pays Rs.306 for it.
A. 11%
B. 13%
C. 15%
D. 18%

Answer 1

Hint: We will first calculate the discount after first discount. Then, subtract the discount from the listed price to find the price after discount. Now, find the discounted price after the second successive discount. Let the second discount be $x\% $ and use the given condition to find the value of $x$.

Complete step-by-step answer:
We have been given that the price of the watch is Rs.400.
We will calculate the price of the watch after giving a discount of 10%.
If the discount is 10% , the amount of discount is 10% of 400 which is equal to
$\dfrac{{10}}{{100}} \times 400 = 40$
After subtracting Rs.40 from the listed price of watch, we will get the price of the watch after first discount.
$400 - 40 = 360$
Let the second discount be $x\% $
Then, we are given that after giving $x\% $ on Rs.360, the cost of the watch becomes Rs.306
Let us now calculate the discounted price by subtracting 306 from 360
$360 - 306 = 54$
Hence, $x\% $ of 360 is 54
$
  \dfrac{x}{{100}} \times 360 = 54 \\
   \Rightarrow x = \dfrac{{54 \times 100}}{{360}} \\
   \Rightarrow x = 15 \\
$
Therefore, the required percentage is 15%
Hence, option C is correct.

Note: Percentage is the number that represents a fraction of 100. For example, the number 67% is equivalent to fraction $\dfrac{{67}}{{100}}$ and decimal 0.67. Successive discount means that the discount on discount.