CameraIcon

SearchIcon

MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Experimental/Empirical Probability

There are 20 ...

Question

There are 20 red balls and 15 green balls in a box. If some red balls are to be subtracted from the box so that the probability of randomly drawing a red ball becomes $\frac{2}{5}$ , then how many red balls must be subtracted from the box ?

Open in App

Solution

Let x be the number of red balls to be subtracted.
According to the question,
$\frac{20 - x}{35 - x} = \frac{2}{5}$

$5 (20 - x) = 2 (35 - x)$
$100 - 5 x = 70 - 2 x$
$x = 10$

Suggest Corrections

thumbs-up

0

Similar questions

Q. A box contains 12 balls of which some are red in colour . If 6 more red balls are put in the box and a ball is drawn at random , the probability of drawing a red ball doubles than what it was before . Find the number of red balls in the box .

^{'} A^{'}

2

3

2

black balls. Another box

^{'} B^{'}

4

2

3

black balls. If two balls are drawn at random, without replacement, from a randomly selected box and one ball turns out to be white while the other ball turns out to be red, then the probability that both balls are drawn from box

^{'} B^{'}

^{'} A^{'}

2

3

2

black balls. Another box

^{'} B^{'}

4

2

3

black balls. If two balls are drawn at random, without replacement, from a randomly selected box and one ball turns out to be white while the other ball turns out to be red, then the probability that both balls are drawn from box

^{'} B^{'}

Q. There are 6 red balls and 8 green balls in a bag. 5 balls are drawn at random and placed in a red box, the remaining 9 balls are put in a green box. The probability that the number of red balls in the green box plus the number of green balls in the red box is not a prime number is

Q. A box contains 5 black and 5 red balls. Two balls are randomly picked one after another from the box, without replacement. The probability for both balls being red is

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Experimental Probability

MATHEMATICS

Watch in App

explore_more_icon

Explore more

Experimental/Empirical Probability

Standard IX Mathematics

Join BYJU'S Learning Program

CrossIcon