1 votes 1 votes A box has $450$ balls, each either white or black, there being as many metallic white balls as metallic black balls. If $40 \%$ of the white balls and $50 \%$ of the black balls are metallic, then the number of non-metallic balls in the box is Quantitative Aptitude cat2021-set2 quantitative-aptitude percentage numerical-answer + – soujanyareddy13 asked Jan 20, 2022 • retagged Mar 23, 2022 by Lakshman Bhaiya soujanyareddy13 2.7k points 1.1k views answer comment Share See all 0 reply Please log in or register to add a comment.
1 votes 1 votes Let’s draw the table for better understanding. $$\begin{array}{|l|ccc|} \hline & \textbf{Black} & \textbf{White} & \\\hline \text{Metallic} & x & x & \\ \text{Non-metallic} & x & 1.5x & \\ \text{Total} & 2x & 2.5x & 450 \\\hline \end{array}$$ Now, $2x+2.5x = 450$ $\Rightarrow 4.5x = 450$ $\Rightarrow \boxed{x = 100}$ $\therefore$ The number of non-metallic balls $\text{(Black+White)}= x+1.5x = 2.5x = 2.5 \times 100 = 250.$ Correct Answer : $250$ Anjana5051 answered Feb 5, 2022 • edited Feb 13, 2022 by Lakshman Bhaiya Anjana5051 11.7k points comment Share See all 0 reply Please log in or register to add a comment.