Hi I tried solving the question what we are actually trying to calculate is the probablity of the white ball being select at every iteration. According to one of the test cases the excepted input was - :

6 4 BWBBBW

and the output was - : 1.8555555556

Now according to the explation let us try to solve it manually taking the following example - :

In the first iteration we would have something like this

    We could either select the white ball at the second 
    place and have the next set as - BBBBW or BWBBB(if we excluded the 
    ball at the last place)

    The probablity of picking up the first white ball however would be 
    1/6+1/6+0+0+1/6+1/6 = 2/3 = 0.66666

    Now in the next case lets suppose we picked up BBBBW
    The probablity of picking up a white ball here would be
    (2/5*1/2) - (Here 1/2 is the probablity of picking up
    the lot from 2 lots from 1st iteration)

    Similarly if picked up the other lot that would be BWBBB. 
    The probablity of picking up a white ball again would be(2/5*1/2)

    Total Probablity would be the 2/3+2/5 = 16/15 = 1.06667
    The excepted output is 1.8555556

Can somebdoy please explain what am I doing wrong here?

Hi everyone,

I'm dealing with some precision issues. For example expected > 19.4431179137 calculated > 19.4431084624 (before formatting : 19.443108462398186) I'm not making any roundings in my calculation, and I'm using Pyton 3 ... any hints ?

Facing the same problem.