Gold is 19 times as heavy as water and copper is 9 times as heavy as water. In what ratio should these be mixed to get an alloy which is 15 times heavy as water?

3 : 2

Considering, Gold - G, Water - W & Copper - C

\(\frac{G}{W}\) = \(\frac{19}{1}\)

\(\frac{C}{W}\) = \(\frac{9}{1}\)

    G    :    C    :    W

   19    :    9    :    1

Water is constant 

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