Question

    Two alloys are made by mixing copper and zinc in the ratio of 3:2 and 5:3, respectively. If equal quantities of the alloys are melted to form a third alloy, find the ratio of copper to zinc in the new alloy.

    A 25:14 Correct Answer Incorrect Answer
    B 23:13 Correct Answer Incorrect Answer
    C 21:14 Correct Answer Incorrect Answer
    D 49:31 Correct Answer Incorrect Answer

    Solution

    Let the quantity of each alloy be 1 unit. For the first alloy, copper = 3/5 and zinc = 2/5 For the second alloy, copper = 5/8 and zinc = 3/8 Now, in the new alloy, copper = (1 × 3/5 + 1 × 5/8) / 2 = (24 + 25) / 40 = 49/40 Zinc = (1 × 2/5 + 1 × 3/8) / 2 = (16 + 15) / 40 = 31/40 The ratio of copper to zinc in the new alloy = 49:31 Correct answer: d

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