7/10*6/9 = 7/15
hows the second draw probability 6/9 here? wont it depend on first draw. I mean if:
A) first draw resulted into one of the stamp in peter's collection, this probability would be : 7/9
B) first draw did not result into perter's collection stamps, second draw probability would be:
As first draw probability remains same, the total probability would be:
7/10 * 7/9 + 7/10 * 6/9 or 91/90
Guess ans to this question depends/changes on if:
- both stamps are drawn "together"
- stamps are drawn one after another.
The ans will vary based on the two.