Civil Services Prep

Prelims 2026 · CSAT / Quantitative Aptitude · Question 65

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?<br/>

  1. 1:3
  2. 3:1
  3. 2:3
  4. 3:2

Answer

1:3

Let amounts of P and Q be x and y. For equal copper and zinc in R: 0.2x + 0.6y = 0.8x + 0.4y. So 0.2y = 0.6x, hence y = 3x. Therefore P : Q = 1 : 3.

  1. X receives three coins of different denominations : 1, 2, 5, 10 and 20. If the total amount received by X is…
  2. For two distinct real numbers x and y, which of them is bigger? Statement I : x^2 Statement II : y
  3. If x and y are integers, then is x even? Statement I : x^2 y^2 is even. Statement II : 1 + x^2 + y^2 is odd.
  4. X is a collection of certain odd numbers whereas Y is a collection of certain even numbers. T consists of the…
  5. If x, y and z are integers, each greater than 1, then is x a prime number? Statement I : xy^2 = 116 Statement…
  6. Which of the following conclusions are valid? 1. Seven Sanskriti Angans, representing different regions of…