The sale price of an article including the Sales Tax is Tk. 616. The rate of Sales Tax is 10%. If the shopkeeper has made a profit of 12%, then the cost price of the article is-

Question: The sale price of an article including the Sales Tax is Tk. 616. The rate of Sales Tax is 10%. If the shopkeeper has made a profit of 12%, then the cost price of the article is-

Solution:
Let,
Cost price be x.
Selling price = x + 12% of x
= x + (12x/100)
= 28x/25

ATQ,
(28x/25) + 10% of (28x/25) = 616
⇒ (28x/25) + (280x/2500) = 616
⇒ (28x/25) + (14x/125) = 616
⇒ (140x + 14x)/125 = 616
⇒ 154x = 77000
∴ x = 500

∴ Cost price tk. 500.