An alloy P contains 20% copper and 80% zinc by weight. Another alloy Q contains 60% copper and 40% zinc by weight. A third alloy R is to be prepared from P and Q so that it contains equal amount of copper and zinc. In what ratio, amounts of P and Q be mixed in order to get R?

Question

Accepted Answer

1 : 3. Let x kg of P be mixed with y kg of Q. Copper in mixture = 0.20x + 0.60y. Zinc in mixture = 0.80x + 0.40y. For equal copper and zinc: 0.20x + 0.60y = 0.80x + 0.40y → 0.20y = 0.60x → y = 3x → x:y = 1:3. Hence P and Q are mixed in the ratio 1:3.

An alloy P contains 20% copper and 80% zinc by weight. Another alloy Q contains 60% copper and 40% zinc by weight. A third alloy R is to be prepared from P and Q so that it contains equal amount of copper and zinc. In what ratio, amounts of P and Q be mixed in order to get R?

Explanation

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