Question

bag contains 5 red balls and some Blue Balls if the parity of drawing of the ball is double that of a red ball find the number of balls in a bag​

Answer 1

Answer:

No. of blue balls :- 10

Total No. of balls :- 15

Correct Question :-

bag contains 5 red balls and some Blue Balls if the probability of drawing of the ball is double that of drawing a red ball. find the number of balls in a bag

Explanation :-

Let the No. of Blue balls in bag be x respectively,

Its Given that the Total No. of Red balls in bag = 5

Total No. of ball will be

No. of Blue balls + No. of Red balls = (x + 5)

P(E) = No. of favourable outcomes / Total No. of outcomes

P( Getting a Red ball ) = 5/(x + 5)

P( Getting a Blue ball ) = x /(x + 5)

According or the statement its given that the Probabilty of Blue ball is double that of a Red ball

Therefore,

$2( \frac{5}{(x + 5)} ) \: = \frac{x}{(x + 5)}$

$10(x + 5) \: = {x}^{2} + 5x$

$x ^{2} - 10x + 5x - 50 = 0$

$x(x - 10) + 5(x - 10) = 0$

$(x - 10)(x + 5) = 0$

$x = 10 \: or \ x \: = - 5$

Therefore, The No. of Blue balls are 10 because No. of ball a can't be negative

Total No. of ball = (x + 5)

= 10 + 5

= 15

Therefore, the total no. of balls in the bag is 15.

Answer 2

Answer

let the no: of blue balls be x                                                                                                          no:of red balls =5                                                                                                                total no:of balls=5+x                                                                                                            probability of blue ball=2*probability of red ball                                                                probability of blue ball=x/5+y                                                                                                      probability of red ball=5/5+y                                                                                    y/5+y=2*5/5+y                                                                                                                    cut both 5+y                                                                                                                        so,                                                                                                                                     y=2*5                                                                                                                                           =10                                                                                                                                            so,no:of blue balls=10