Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: the sale price of a trolley bag including the sale tax is rs . 420 . the rate of sale tax is 12 % . if the shopkeeper has made a profit of 25 % , the cost price of the trolley bag is :
rs 300
Rs. 308.89.