Percentages Question 4 - CAT 2021
Question
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
Step-by-Step Explanation
Let the number of white balls be x and black balls be y.
x + y = 450
Since the number of metallic white and metallic black balls are equal,
0.4x = 0.5y
Solving,
x = 250, y = 200
Non-metallic balls:
- White = 60% of 250 = 150
- Black = 50% of 200 = 100
Total non-metallic balls:
150 + 100 = 250
Hence, the correct answer is 250.
đź’ˇ FundaMakers Tip: When two percentages are equal, convert them into an equation first. It makes the calculation straightforward.