Math
posted by Lola
One bag contains 4 white balls and 3 black balls. If someone draws one ball from the bag and then replaces it and draws another, what is the probability that both will be black?
A: 8/12
B: 9/49
C: 1/6
D: 3/7

Reiny
Do you think the balls remember what happened to them on the first draw when you do the second draw ?
What is the prob of drawing a black ball the first time? 
Lola
Is it A?

Reiny
Why do you think it is A? are you guessing?
What is the prob of getting a black in the first draw? 
Lola
the prob is 3/4 i think

Lola
OHHH IS IT D??

Reiny
no and no
There are 7 balls in the bag of which 3 are black
So the prob of drawing a black the first time is 3/7
So what will happen the second draw??
What is the answer to the first question I asked you? 
Lola
Oh b: 9/49

Reiny
You got it!!
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