Question 1131632
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There is a bag filled with 3 blue and 4 red marbles. 
A marble is taken at random from the bag, the color is noted and then {{{highlight(cross(it))}}} <U>the ball</U> is {{{highlight(cross(replaced))}}} <U>returned back</U> to the bag. 
Another marble is taken at random. 
What is the probability of getting 2 blues?
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<U>ANSWER</U>.  {{{(3/(3+4))*(3/(3+4))}}} = {{{(3/7)^2}}} = {{{9/49}}}.


The formula is self-explanatory.
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