Question 667908
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Hi,
A box contains {{{10}}}balls: 7 red balls and 3 black balls. 
Two balls are drawn.
with replacement
P(red than black) = {{{(7/10)(3/10)= 21/100}}}
without replacement
P(black than black) = {{{(3/10)(2/9)= 6/90= 1/15}}}