An alloy P contains 20% copper and 80% zinc by weight. Another alloy Q contains 60% copper and 40% z — CSAT 2026 Answer & Explanation

2026

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

Let the amounts of alloys P and Q be $x$ and $y$ respectively. The copper content is $0.2x + 0.6y$ and zinc content is $0.8x + 0.4y$ . Setting these equal for alloy R gives $0.2x + 0.6y = 0.8x + 0.4y$ . Simplifying leads to $0.2y = 0.6x$ or $x/y = 1/3$ , implying P and Q should be mixed in the ratio of 1:3.

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