P and Q purchase two different articles at same price. Later on R purchases both articles at same price of ₹ 390 each from P and Q. But profit of P was x% while profit of Q was y%, since Q calculates his profit on SP. If R sells one of the articles to S at y% profit, then what is the cost price for S if y = \(38 \frac{6}{13}\)% of x?