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ഒരു മീറ്റിങ്ങിലെ ആളുകൾ പരസ്പരം ഹസ്തദാനം ചെയ്തപ്പോൾ 66 ഹസ്തദാനങ്ങൾ നടന്നു എന്നാൽ മീറ്റിങ്ങിൽ പങ്കെടുത്ത ആളുകളുടെ എണ്ണം എത്ര ?

A10

B11

C12

D13

Answer:

C. 12

Read Explanation:

n(n-1)/2 =66 n(n-1)= 132 n^2-n-132 = 0 (n+11)(n-12) = 0 n = -11 , 12 so 12


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