24ans is 2012
Q1 A bag contains 10 white and 10 black balls.A perosn draws two balls at a time without replacementand rpeleats till bag is empty.The probablity tha the draws the balls of same color each time
Q2 The number of ordered pairs (a,b) where a,b ε R such that
(a+ib)2010=a-ib is ??
-
UP 0 DOWN 0 1 5
5 Answers
112) I don't get the 2nd qsn,
|z|=1
So
\left(a,b \right)=\left(cos\frac{n\pi}{2009},sin\frac{n\pi}{2009} \right) satisfies this - (if I've not made any blunder anywhere)
106lzl2010 = lzl
=> lzl=0
or lzl=1
If lzl =0, then a=b=0 (1 case)
If lzl=1,
z2010 = z = 1/z
=> z2011 = 1
So in this case we get 2011 solutions..
So total 2012 solutions
110 white and 10 black
firstly total no.of arrangment of wwwwwbbbbb =10!/(5!)2
P of any one such event 120C10 hence answer is 10C520C10
Is it correct ?