CAT 2021 Slot 2 · Quant · Question 7
CAT 2021 Slot 2 previous year question on Percentage, with the answer and a step-by-step solution.
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
Answer & solution
Answer: 250
Let there be W white and B black balls, so W+B=450.
Equal numbers of metallic balls of each colour gives 0.4W=0.5B, that is 4W=5B, so W=\frac{5B}{4}.
Then \frac{5B}{4}+B=450, so \frac{9B}{4}=450, giving B=200 and W=250.
Non-metallic balls are 60\% of the white and 50\% of the black: 0.6\times 250+0.5\times 200=150+100=250.
More Percentage questions
- Q8Identical chocolate pieces are sold in boxes of two sizes, small and large. The large box is sold for twice the price…CAT 2021 Slot 1 · Quant · Percentage
- Q14In a class, there were more than 10 boys and a certain number of girls. After 40% of the girls and 60% of the boys…CAT 2025 Slot 1 · Quant · Percentage
- Q21Kamala divided her investment of ₹100000 between stocks, bonds, and gold. Her investment in bonds was 25% of her…CAT 2025 Slot 1 · Quant · Percentage
- Q22A certain amount of money was divided among Pinu, Meena, Rinu and Seema. Pinu received 20% of the total amount and…CAT 2025 Slot 2 · Quant · Percentage
- Q10The total of male and female populations in a city increased by 25% from 1970 to 1980. During the same period, the…CAT 2021 Slot 3 · Quant · Percentage
- Q14In a tournament, a team has played 40 matches so far and won 30% of them. If they win 60% of the remaining matches,…CAT 2021 Slot 3 · Quant · Percentage
Take this paper as a timed test
Real exam timing, instant score, rank and topic-wise analysis.