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MAT Exam 2023 Paper

Question : 107 of 200

Marks: +1, -0

Solution:

Concept:

Use the fraction of zinc in each alloy and apply the rule of alligation.

Explanation:

Let the two alloys be mixed in the ratio

x : y

Zinc fraction in first alloy =

\frac{3}{3+1} = \frac{3}{4}

Zinc fraction in second alloy =

\frac{5}{5+1} = \frac{5}{6}

Zinc fraction in new alloy =

\frac{4}{4+1} = \frac{4}{5}

So,

\frac{\frac{3}{4}x + \frac{5}{6}y}{x+y} = \frac{4}{5}

Multiply both sides by 60:

60\left(\frac{3x}{4} + \frac{5y}{6}\right) = 60\left(\frac{4}{5}(x+y)\right)

\Rightarrow 45x + 50y = 48x + 48y

\Rightarrow 2y = 3x

\Rightarrow x : y = 2 : 3

This ratio is not present in the given options.

Answer:

D. None of the above

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