A box has 100 blue balls, 50 red balls, 50 black balls, 25% of blue ba

1.	A box has 100 blue balls, 50 red balls, 50 black balls, 25% of blue balls and 50% of red balls are taken away. Percentage of black balls at present is 1). 50%2). 25%3). \(33\frac{1}{3}\%\)4). 40%
Answer» The box has 100 blue BALLS, 50 RED balls, 50 black balls. 25% of blue balls are taken away. Now, number of blue balls present in the box: = 100 – [25% of 100] = 100 – 25 = 75 50% of red balls are taken away. Now, number of red balls present in the box: = 50 – [50% of 50] = 50 – 25 = 25 Total number of balls present in the box now: = number of blue balls + number of black balls + number of red balls = 75 + 50 + 25 = 150 ∴ PERCENTAGE of black balls at present is: $(\frac{{{\rm{number\;of\;black\;balls\;present}}}}{{{\rm{Total\;number\;of\;balls\;present\;}}}} \TIMES 100)$ $(= \left[ {\frac{{50}}{{150}} \times 100} \right]\%)$ $(= \;\frac{{100}}{3}\%)$ $(= 33\frac{1}{3}\%)$

A box has 100 blue balls, 50 red balls, 50 black balls, 25% of blue balls and 50% of red balls are taken away. Percentage of black balls at present is 1). 50%2). 25%3). $33\frac{1}{3}\%$4). 40%

Answer»

The box has 100 blue BALLS, 50 RED balls, 50 black balls.

25% of blue balls are taken away.

Now, number of blue balls present in the box:

= 100 – [25% of 100]

= 100 – 25

= 75

50% of red balls are taken away.

Now, number of red balls present in the box:

= 50 – [50% of 50]

= 50 – 25

= 25

Total number of balls present in the box now:

= number of blue balls + number of black balls + number of red balls

= 75 + 50 + 25

= 150

∴ PERCENTAGE of black balls at present is:

$(\frac{{{\rm{number\;of\;black\;balls\;present}}}}{{{\rm{Total\;number\;of\;balls\;present\;}}}} \TIMES 100)$

$(= \left[ {\frac{{50}}{{150}} \times 100} \right]\%)$

$(= \;\frac{{100}}{3}\%)$

$(= 33\frac{1}{3}\%)$

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