Two urns contain white b***s and yellow b***s. The first urn contains 9 white b***s and 9 yellow b***s and the second urn contains 8 white b

Here's another way to do this....

We want to draw one white ball from nine in the first urn....and there are 18 ways to choose one ball from the first urn

Then, we want to draw one white ball from the second urn......and there are 11 ways to choose a ball from the second urn

So we have......

C(9, 1)/ C(18,1)  x  C(8,1) / C(11, 1)  =

( 9 / 18 ) x ( 8  / 11) =

(1 /2 ) x (8 / 11) =

8 / 22 =

4 / 11 =

about  36.36%

9/18=0.5

8/11=0.727

0.727+0.5=1.227

1.227/2=0.6135

So about 61.35%

Not sure if correct,  but it looks good to me.....

$$\\P(WW)=\frac{9}{18}\times\frac{8}{11}$$

Hi Happy,

Good guess -  but not quite  

9/18*8/11=72/198

72/198=4/11

I'm horrible with probabiltiy.......

For a bonus:

The probability is 4/11,0.3636363,or 36.36%