If x : y : z = 1 : 2 : 3, then what the value of \(\left(\frac{3x^2 - 2y^2 + 4z^2}{x^2 + 2y^2 + z^2}\right)\)
\(\tfrac{31}{21}\)
\(\tfrac{31}{16}\)
\(\tfrac{31}{18}\)
\(\tfrac{31}{19}\)
'A' sells an article to 'B' at 12% profit. 'B' sells it to 'C' at 9% loss. If 'C' pays ₹15,288 for it, then at what price (in ₹) is the article sold by A?