Question

what will be the sum of adding all the possible 4 digit numbers formed by 7,9,1,3 using each of the digits only once?
[133220,122320,133230,133320]
[Hint - each of the given digits will occur 6 times in the units place and there will be 4 groups of 6 numbers each]​

Answer 1

Step-by-step explanation:

Since it's a 4 digit number, each digit will appear 6=24/4 times in each of units, tens, hundreds, and thousands place. Therefore, the sum of digits in the units place is 6(7+9+1+3)=120.

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