Two successive discounts, each of x% on the marked price of an article, are equal to a single discount of Rs 331.20. If the marked price of the articles is Rs 920, then the value of x is :
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 20.
Single discount = Rs. 331.20
Marked price = Rs. 920
Selling price = Marked price - discount
1st discount = x% of 920 = Rs. 9.2x
He/she have to pay amount = Rs. (920 - 9.2x)
2nd discount = x% of Rs. (920 - 9.2x) = (920 – 9.2x)x/100
Accordingly -
9.2x + x(920 - 9.2x)/100 = 331.20
9200x + 9200x - 92x2 = 331200
92x2 - 18400x + 331200 = 0
x2 - 200x + 3600 = 0
x2 - 180x - 20x + 3600 = 0
(x - 180)(x - 20) = 0
x = 180 or x = 20
180% is invalid as per the question.
Thus, the value of x is 20.