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    A and B are two alloys formed by the combination of gold and copper in the ratio 5 : 3 and 5 : 11 respectively. Equal quantities of these two alloys a
    Question

    A and B are two alloys formed by the combination of gold and copper in the ratio 5 : 3 and 5 : 11 respectively. Equal quantities of these two alloys are melted and mixed to form a new alloy C. Now, alloy C contains gold and copper in the ratio:

    A.

    33 : 25

    B.

    15 : 17

    C.

    17 : 15

    D.

    25 : 23

    Correct option is B

    Given:

    Alloy A is formed by the combination of gold and copper in the ratio 5:3.

    Alloy B is formed by the combination of gold and copper in the ratio 5:11.

    Equal quantities of alloys A and B are melted and mixed to form a new alloy C.

    Solution:

    Gold in alloy A: 58\frac{5}{8}​ of the total quantity (since 5 parts out of 8 are gold).

    Copper in alloy A:38 \frac{3}{8}​ of the total quantity.

    Gold in alloy B:516 \frac{5}{16} ​of the total quantity (since 5 parts out of 16 are gold).

    Copper in alloy B: 1116 \frac{11}{16}​ of the total quantity.

    Let the equal quantity of alloys A and B used in the mixture be x.

    Gold in A =58×x \frac{5}{8} \times x

    Copper in A =38×x \frac{3}{8} \times x

    Gold in B = 516×x \frac{5}{16} \times x

    Copper in B =1116×x \frac{11}{16} \times x

    Total Gold in Alloy C:

    Total Gold = 58x+516x=1016x+516x=1516x\frac{5}{8}x + \frac{5}{16}x = \frac{10}{16}x + \frac{5}{16}x = \frac{15}{16}x

    Total Copper in Alloy C:

    Total Copper = 38x+1116x=616x+1116x=1716x\frac{3}{8}x + \frac{11}{16}x = \frac{6}{16}x + \frac{11}{16}x = \frac{17}{16}x​​

    Ratio of Gold to Copper =1516x1716x=1517 \frac{\frac{15}{16}x}{\frac{17}{16}x} = \frac{15}{17}

    The ratio of gold to copper in alloy C is 15:17.

    Alternate Method:


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