Question 1152095
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I edited your post in THIS WAY :


<pre>
    When rolling a dice, what is the probability that it will take at most 3 throws until a six occurs on a dice ?
</pre>


<U>Solution</U>


<pre>
    P =   P(getting 6 at the first rolling) + 

        + P(getting 6 at the second rolling and not getting it at the first rolling) + 

        + P(getting 6 at the third rolling and not getting it NEITHER at the 1-st NOR at the 2-nd rolling) = 


        = {{{1/6}}} + {{{(5/6)*(1/6)}}} + {{{(5/6)*(5/6)*(1/6)}}} = 

        = {{{1/6}}} + {{{5/(6*6)}}} + {{{25/6^3}}} = {{{6^2/6^3}}} + {{{(6*5)/6^3}}} + {{{25/6^3}}} = {{{(36 + 30 + 25)/6^3}}} = {{{91/216}}} = 0.421296 = 42.1296%.    <U>ANSWER</U>
</pre>

Solved.