Stats help.
Q.A bag contains balls,numbered from 1 to 11.Two balls are drawn without replacement.What is the probability that both will be of even numbers.

Question

Stats help.
Q.A bag contains balls,numbered from 1 to 11.Two balls are drawn without replacement.What is the probability that both will be of even numbers.

hartnn · Answer

how many even number of balls and how many total balls ?

uri · Answer

2,4,6,8,10 and 11 balls.

hartnn · Answer

ok, so # even balls = 5 
# total balls =11

2 balls drawn without replacement means 
1st a ball is drawn and we do not put that ball back in the bag and another ball is drawn
(similar to last Q of 2 cards drawn)

hartnn · Answer

so, when we draw 1st ball, what will be the probability that its even numbered ?

hartnn · Answer

P(even # ball) = # of even balls / total # of balls =... ?

uri · Answer

5/11

hartnn · Answer

correct! 
now how many even balls remain ? 
how many total balls remain ?

uri · Answer

4/10

anonymous · Answer

5/11 is the probability of the first even no, and 4/10 will be of second

uri · Answer

I already said that xD

anonymous · Answer

P(A U B) = P(A)+P(B)

uri · Answer

So 5/11 x 4/10 =0.1818

uri · Answer

@VV-EFF Ayee I don't like that formula.

anonymous · Answer

hhmmmm! formula choro! logic banao! ;)

hartnn · Answer

5/11 x 4/10 =0.1818 is correct ....

anonymous · Answer

@hartnn careful.....

uri · Answer

Thankyou @hartnn bhai. :3

uri · Answer

and @VV-EFF Wasiq bhai.

anonymous · Answer

its Wasay bhai not wasiq bhai :P

uri · Answer

Oh sorry *Wasay my bad :3