SOLUTION: there are 5 red balls and 6 black balls in a bowl ,two balls are picked up at random simultaneously. what is the probability of two balls being same colour

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Question 881583: there are 5 red balls and 6 black balls in a bowl ,two balls are picked up at random simultaneously. what is the probability of two balls being same colour
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
With replacement,
P%28R%29=5%2F11
P%28R%2CR%29=%285%2F11%29%285%2F11%29=25%2F121
P%28B%29=6%2F11
P%28B%2CB%29=6%2F11%29%286%2F11%29=36%2F121
So together,
P=25%2F121%2B36%2F121=61%2F121
.
.
.
Without replacement,
P%28R%2CR%29=%285%2F11%29%284%2F10%29=2%2F11
P%28G%2CG%29=%286%2F11%29%285%2F10%29=3%2F11
So together,
P=2%2F11%2B3%2F11=5%2F11