Find the ratio of average of selling price of each unit of articles 'B' and 'C' together to cost price of each unit of article 'A'

Given,   2x – y/2 = 90   Or, 4x - y = 180 ....... (I)   And, 3y – x/2 = 35   Or, (6y - x) = 70 ........ (II)   On adding equation (I) with 4 × equation (II), we have;   4x + (-4x) - y + (24y) = 180 + 70 X 4   Or, 23y = 460   So, y = 20   So, 4x = 180 + 20 ..... (From equation I)   Or, x = 200 ÷ 4 = 50   So, marked price of article 'A' = 4 × 50 = Rs. 200   And, percentage discount offered on article 'A' = 1.25y% = 1.25 × 20% = 25%   So, discount offered = 200 × 0.25 = Rs. 50   So, profit earned on article 'A' = 50 × 1.4 = Rs. 70   So, profit earned on article 'D' = 70 + 50 = Rs. 120   Marked price of article 'D' = Rs. 400   Percentage discount offered = 2y% = 2 × 20 = 40%   So, discount offered = 400 × 0.4 = Rs. 160   ATQ;   (120/160) × 100 = {z - (x/2)}   Or, 75 = z - 25   So, z = 100   For article 'A':   Marked price of the article = Rs. 200   Discount offered = Rs. 50   Selling price = 200 - 50 = Rs. 150   Profit earned = Rs. 70   So, cost price = 150 - 70 = Rs. 80   Average selling price of articles 'B' and 'C' together = (240 + 360) ÷ 2 = Rs. 300   Cost price of article 'A' = Rs. 80   So, required ratio = 300:80 = 15:4