Cost price of items bought by Gauri in the stationers = 25
Price after deducting sales tax = 25 - 0.30 = 24.70
Let the amount of sales tax on taxable purchases be x
Then, 6\(\%\) of x = 0.3 rs
x \(=(0.3)(\frac{100}{6})\)
x = 5
Cost price of the tax free items = 24.70 - 5 = 19.70
Hence, option C is the correct answer.The correct option is (C): Rs.19.70