What will
be the sum of adding all the possible four-digit numbers formed by7,9,1,3
using each of the digits only once?
1)133220 2) 122320 (3) 133230 (4) 133320
Hint :each of the given digits will occur six times in the units place and there will be 4
groups of 6 numbers each
plz ans step by step
Answers
Answered by
3
Step-by-step explanation:
our digit numbers =4⋅3⋅2⋅1=24
=
4
⋅
3
⋅
2
⋅
1
=
24
ways we can form a four digit number. Since it's a 4 digit number, each digit will appear 6=24/4
6
=
24
/
4
times in each of units, tens, hundreds, and thousands place. Therefore, the sum of digits in the units place is 6(1+2+5+6)=84
6
(
1
+
2
+
5
+
6
)
=
84
.
Why they are adding 1+2+5+6
1
+
2
+
5
+
6
?
Similarly sum of digits at tens,hundreds,thousands place is 84
84
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