rkrish...now plz ans this one....more simplified...
Out of 2 consecutive integers two are chosen...find the probability that their sum is odd
Out of 46 consecutive integers two are chosen...find the probability that their sum is odd
rkrish...now plz ans this one....more simplified...
Out of 2 consecutive integers two are chosen...find the probability that their sum is odd
actually we can not pick 1 twice out of 1,2
thatz the mistake i did
thanx rkrish...
i think i got it...we can not pick the same no. twice...as we r taking it simultenously.....not one after another..
arrey yaar.....its not like that...dekho....
why 1st one & 2nd one...
even & odd ya odd & even kya fark padta hai.
you have to choose two nos.
one odd no. out of 23 & one even no. out of 23.
kitne hue ?? 23C1 for odd & 23C1 for even.
So, fav case hua 23C1 * 23C1 = 23 * 23
Abhi sample space toh nahi badlega....46 nos. mein se you have to choose 2 nos.
So sample space = 46C2 = (46*45)/2 = 23*45
Hence P = (23*23)/(23*45) = 23/45
picking up numbers are not like picking up balls....u can pick the same no. second time....
[45]
odd no. 23
even no. 23
first one to be even 23/46
then second one to be odd 23/46(not 23/45...because the sample space does not change)
so probab 1/2*1/2=1/4
again
first one to be odd 23/46
then second one to be even 23/46...
so final ans 1/2
ee e
oo e
eo o
oe o
There are 23 even & 23 odd nos. out of the 46
Fav. case = 1 odd & 1 even = 23C1 * 23C1 = 23*23
Sample space = 46C2 = 23*45
P = (23*23)/(23*45) = 23/45