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SSC Selection Post 2019 PYQ — Question 72

SSC Selection Post - Graduation Level 2019 - 16 Oct 2019 • Quantitative Aptitude • Q72

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Alloys A and B contain copper and zinc in the ratio 1: 3 and 3: 5, respectively. In what ratio A and B be mixed to get a new alloy containing copper and zinc in the ratio 1: 2?
 

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Correct answer: C

Explanation

The correct answer is Option 3 i.e. 1:2.

A: Cu ratio = 1/4​

B: Cu ratio = 3/8​

Target: Cu ratio = 1/3​

Use allegation:

A : B=38−1313−14=124÷112=12\text{A : B} = \frac{\frac{3}{8} - \frac{1}{3}}{\frac{1}{3} - \frac{1}{4}} = \frac{1}{24} \div \frac{1}{12} = \frac{1}{2}