Solution:For I:
Cost price of articles ‘A’ and ‘B’ together = 1200 × 2
= Rs. 2400
Cost price of article ‘A’ = (2400 - 480)/2 = Rs. 960
Cost price of article ‘B’ = 2400 - 960 = Rs. 1440
Selling price of both articles = 0.80 × 1.75 × 960 + 1.40 × 1440 = Rs. 3360
Profit earned = 3360 - 2400 = Rs. 600 < 960 < 1200
So, ‘I’ can be the answer.
For II:
Cost price of articles ‘A’ and ‘B’ together = 1200 × 2
= Rs. 2400
Cost price of article ‘A’ = (2400 + 800)/2 = Rs. 1600
Cost price of article ‘B’ = 2400 - 1600 = Rs. 800
Selling price of both articles = 0.60 × 1.75 × 1600 + 1.40 × 800 = Rs. 2800
Profit earned = 2800 - 2400 = Rs. 400 < 600
So, ‘II’ cannot be the answer.
For III:
Cost price of articles ‘A’ and ‘B’ together
= 1200 × 2 = Rs. 2400
Cost price of article ‘A’ = (2400 + 400)/2 = Rs. 1400
Cost price of article ‘B’ = 2400 - 1400 = Rs. 1000
Selling price of both articles = 0.90 × 1.75 × 1400 + 1.40 × 1000 = Rs. 3605
Profit earned = 3605 - 2400 = Rs. 1205 > 1200
So, ‘III’ cannot be the answer.