What is the sum of all 3 digit positive integers that can be formed using the digits 1, 3, and 5, if the digits are allowed to repeat within a number?  Answers.
A) 4551	B) 5661	C) 6771	D) 7881	E) 8991
The number of these 3-digit numbers is   3*3*3= 
<gadget id="calculator">  3*3*3</gadget>
<output>27</output>
27   Each digit 1, 3, and 5 will appear in the ones, tens, and hundreds place 9 times each.   The sum equals 9(111) + 9(333) + 9(555)= 9(999) = 8991   The answer is 8991.
<result>E</result>
What is the sum of all 3 digit positive integers that can be formed using the digits 1, 3, and 5, if the digits are allowed to repeat within a number?