Question

heya guys , can anyone help me out with this question
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.Q
Consider digits 0,1,2,3,4,5,6 . Find the number of 5 digit numbers that can be formed ?
(if repetition of any digit is not allowed)
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answer if you know how to solve
(I need correct ans)

Answer 1

As repetation is not allowed.

So, the 1st choice will be 6, 2nd choice will be 5, 3rd choice will be 4, 4th choice will be 3 and 5th choice will be 2

Hence,The total choice is,
6×5×4×3×2=720

720 number of 5 digit no can be formed.

Answer 2

If repetition of digits is not allowed ,
given digits -(0,1,2,3,4,5,6}

5 digit number can be written as

blanks for 5 digit number ->
ten.Th Th H T U
_ . _ . _ . _ . _

at ten.Th place there can be any number out of 0,1,2,3,4,5,6 except - 0 = 6

similarly ,
at Th place there can be any number out of 7 digit except (number at ten.Th place ) = 6

at H place there can be any number out of 7 digit except ( number at ten.Th & Th place ) = 5

at T place there can be any number out of 7 digit except ( number at ten.Th , Th & H place ) = 4

at U place there can be any number out of 7 digit except ( number at ten.Th , Th ,H & T place ) = 3

so, total no. of 5 digit numbers that can be form by given 7 digits

= 6×6×5×4×3
= 30 × 72
= 2160 numbers