What is the cost painting the two adjacent walls of a hall at Rs. 5 per m2 which has no windows or doors? I. The area of the hall is 24 sq. m. II. The breadth, length and height of the hall are in the ratio of 4 : 6 : 5 respectively. III. Area of one wall is 30 sq. m.

What is the cost painting the two adjacent walls of a hall at Rs. 5 per m2 which has no windows or doors? I.  The area of the hall is 24 sq. m. II.  The breadth, length and height of the hall are in the ratio of 4 : 6 : 5 respectively.  III.  Area of one wall is 30 sq. m.

A. I only B. II only C. III only D. Either I or III E. All I, II and III are required. Answer: Option C Explanation: From II, let l = 4x, b = 6x and h = 5x. Then, area of the hall = (24x2) m2. From I. Area of the hall = 24 m2. From II and I, we get 24x2 = 24         x = 1.  l = 4 m, b = 6 and h = 5 m. Thus, area of two adjacent walls = [(l x h) + (b x h)] m2 can be found out and so the cost of painting two adjacent walls may be found out. Thus, III is redundant.  Correct answer is (C).