<PRE><B>Question 477883</B>
Of 15 windup toys on a sale table, 4 are defective. If 2 toys are selected at random, find the expected number of defective toys. 
----
Random number of defective toys: 0:::::::::1:::::::::::::::::2
Corresponding Probabilities::(11/15)^2::2*(4/15)(11/15)::(4/15)^2
------------

E(x) = 0 + 1[2(44/225)] + 2[16/225] = (88+32)/225 = 120/225 = 24/45
---------------
Cheers,
Stan H.
---------------




</PRE>