Question

g An urn contains 10 balls: 4 red and 6 blue. A second urn contains 16 red balls and an unknown number of blue balls. A single ball is drawn from each urn. The probability that both balls are the same color is 0.44. Calculate the number of blue balls in the second urn.

Answer 1

Answer:

Therefore the of blue in the second urn is 4.

Step-by-step explanation:

Let second urn contain x number of blue ball .

Urn            Red Ball          Blue Ball         Total Ball

1                       4                       6                      10

2                      16                       x                    16+x

Getting a red ball from first urn is $P(R_1)=\frac{\textrm {Number of red ball}}{\textrm {Total ball}}$    $=\frac{4}{10}$

Getting a blue ball from first urn is $P(B_1)=\frac{\textrm {Number of blue ball}}{\textrm {Total ball}}$ $=\frac {6}{10}$

Getting a red ball from second urn is $P(R_2)=\frac{\textrm {Number of red ball}}{\textrm {Total ball}}$    $=\frac{16}{16+x}$

Getting a blue ball from second urn is $P(B_2)=\frac{\textrm {Number of blue ball}}{\textrm {Total ball}}$ $=\frac {x}{16+x}$

Getting two red balls from first and second urn is $=\frac{4}{10}\times \frac{16}{16+x}$

                                                                                  $=\frac{32}{5(16+x)}$

Getting two blue balls from first and second urn is $=\frac{6}{10}\times \frac{x}{16+x}$

                                                                                  $=\frac{3x}{5(16+x)}$

The probability that both balls are the same in color is $=\frac{32}{5(16+x)}+\frac{3x}{5(16+x)}$

Given that the probability that both balls are the same in color is 0.44.

According to the problem,

$\frac{32}{5(16+x)}+\frac{3x}{5(16+x)}=0.44$

$\Rightarrow \frac{32+3x}{5(16+x)} =0.44$

$\Rightarrow \frac {32+3x}{(80+5x)} =0.44$

$\Rightarrow 32+3x =0.44(80+5x)$

$\Rightarrow 32+3x =35.2 +2.2x$

$\Rightarrow 3x -2.2 x= 35.2 -32$

$\Rightarrow 0.8x= 3.2$

$\Rightarrow x = 4$

Therefore the of blue in the second urn is 4.