105713?
1) 7 digits from the nos.1,2,3,...9. are written in a random order. Find the probability that this 7 digit no. is divisible by 9.
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3 Answers
9divisibility check is sum of digit is divisible by 9
please correct me i am getting 1/9
sum of digits is divisible by 9 hence i take these tuples and eliminate from set( 1,8),(2,7),(3,6),(4,5)
i get 1+2+3+4+5+6+7+8+9-(9)=45-9=36
i get 4 sets with 7 elements each
hen permutation is 4x7!
total permutation is 9x8x7x6x5x4x3
total i get 1/9
i know i am wrong kindly correct me with the thing i am missing