Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-35

An alloy contains copper, zinc and nickel in the ratio of 5: 3: 2. The quantity of nickel in kilogram that must be added to 100 kg of this alloy to have the new ratio 5 : 3 : 3 is                                          [SSC (CGL) 2011]

A) 8 kg

B) 10 kg

C) 12kg

D) 15 kg

Correct Answer: B

Solution :

Let quantity of copper be \[5x.\]

Quantity of zinc be \[3x\]

Quantity of nickle be \[2x\]

Now, \[5x+3x+2x=100kg\]

\[\therefore \]Quantity of nickle \[=10\times 2=20\,\,kg\]

Let x kg of nickel be mixed.

Then, \[\frac{20+x}{100+x}=\frac{3}{11}\]

\[\Rightarrow \] \[220+11x=300+3x\]

\[\Rightarrow \] \[11x-3x=300-220\]

\[\Rightarrow \] \[8x=80\]

\[\therefore \] \[x=10\,\,kg\]