Question 1200326
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An urn contains 7 red marbles, 6 white marbles and 10 blue marbles. 
A child randomly selects three (without replacement).

(a) Find the probability all have the same color.

(b) Find the probability that none is white.
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<pre>
(a)  Total possible triples  {{{C[7+6+10]^3}}} = {{{C[23]^3}}} = {{{(23*22*21)/(1*2*3)}}} = 1771.


     Triples of the same color {{{C[7]^3}}} + {{{C[6]^3}}} + {{{C[10]^3}}} = 35 + 20 + 120 = 175.


         P(a) = {{{175/1771}}} = 0.09881  (rounded).    <U>ANSWER</U>



(b)  P(b) = {{{C[7+10]^3/1771}}} = {{{C[17]^3/1771}}} = {{{680/1771}}} = 0.3840  (rounded).    <U>ANSWER</U>
</pre>

Solved.