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Maths Puzzle
Numerical Ability
Probability
in a room there are 7 person,the chance that two of them were born on the same day of the week is.
Read Solution (Total 2)
-
- first select two person from 7 in 7C2 ways.
select a day which they have to be born in 7C1 ways.
for the remanning 5 people select 5days out of 6days of week and no. of arrangment of these 5 people in 5 days = (7C2*7C1*6C5*5!)ways.
also,7 people born on 7 days whould be 7^7
hence
(7C2*7C1*6C5*5!)/(7^7) =2160/7^5 - 10 years agoHelpfull: Yes(1) No(0)
- ans is 7c2*7/5040=147/1716=49/572
- 10 years agoHelpfull: Yes(0) No(0)
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