Two cups X and Y contain coffee and water combined in the ratio 8:5 and 5:2 correspondingly. What is the ratio in these 2 combinations be combined to get a new combination has coffee and a water in the ratio of 9:4?
Choose the correct choice from the following answers: A) 2:5 B) 2:3 C) 2:7 D) 2:9 E) None of these
Explanation :   i) : If C.P. of coffee be Re.1   Given ratio of combination in X= 8:5   Coffee in 1 cup combination in X = (8/13)cups   C.P of 1 cup combination in X= Rs. 8/13   Therefore, The ratio of Combination in Y = 5:2   Coffee in 1 cup combination in Y – (5/7) cups   C.P of 1 cup combination in B = Rs. 5/7   Ratio of new combination = 9:4   milk in 1 cup combination = 9/13   C.P of 1 cup combination = Rs/ 9/13 (Mean price)   ii) : By the rule of allegation,   i. C.P of 1 cup of combination in X =8/13   ii. C.P of 1 cup of combination in Y = 5/7   iii. Mean price (p) = 9/13   iv. d – m = 9/13 – 5-7 = 2/91   v. m – c = 9/13 – 8/13 = 1/13   Needed ratio = 2/91 : 1/13 = 2:7   Answer : 2:7
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Two cups X and Y contain coffee and water combined in the ratio 8:5 and 5:2 correspondingly. What is the ratio in these 2 combinations be combined to get a new combination has coffee and a water in the ratio of 9:4?