# shruti290

## Forum Replies Created

Viewing 4 posts - 16 through 19 (of 19 total)
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• in reply to: probability #517

shruti290
Participant

Thanks

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• in reply to: permutation and combination #510

shruti290
Participant

the correct answer is 36 and yours is 18

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• in reply to: permutation and combination #509

shruti290
Participant

i did not follow what u said and the correct ans is 505 i forgot to mention and i got it
basically the question says tht atleast 2 didigts are identical which is just another way of saying tht at least one digit is repeated therefore the answe is
5^4-5!
that is the total no of ways- no digit repeated

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• in reply to: probability #508

shruti290
Participant

but where is the case where 2 colors will be missing?
what i thought was tht first there are 90c10 ways in total now
case1-draw 10 balls from the 30 red and 30 white balls tht means 60c10
cse 2- 10 balls drawn frm 30 white and 30 blue balls tht means 60c10
case3-10 balls frm 30 red and 30 blue tht emans 60c10
now in all these 3 cases will also involve the cases where only red ,blue or white balss are drawn therefore to avoid double counting we subtract 3*30c10