SSC Sample Paper Mock Test-2 SSC CGL Tear-II Paper-1

A and B are two alloys of gold and copper prepared by mixing metals in the ratio 7 : 2 and 7 : 11, respectively. If equal quantities of alloys are mixed melted to form a third alloy C. Then the ratio of gold and copper in C.

A) 5 : 7

B) 7 : 5

C) 3 : 4

D) 4 : 3

Correct Answer: B

Solution :

Let 1 kg of each one of A and B be taken to form 2 kg of C.

\[\therefore \]Gold in 1 kg of A \[=\frac{7}{9}\]

Copper in 1 kg of A \[=\frac{2}{9}\]

Gold in 1 kg of B \[=\frac{7}{18}\]

Pepper in 1 kg of B \[=\frac{11}{18}\]

Gold in 2 kg of

C\[=\left( \frac{7}{9}+\frac{7}{18} \right)=\frac{14+7}{18}=\frac{21}{18}=\frac{7}{6}\]

Copper in 2 kg of

C \[=\left( \frac{2}{9}+\frac{11}{18} \right)=\left( \frac{4+11}{18} \right)=\frac{15}{18}=\frac{5}{6}\]

\[\therefore \]Ratio of gold and copper in C\[=\frac{7}{6}:\frac{5}{6}=7:5\]