I'm not sure I understand the question.
The 2-digit multiples of 11 are 11, 22, 33, 44, 55, 66, 77, 88, and 99 .
Adam up !
Another, easier and slightly slicker, way to do it would be to factor the list
first, and then do the sum as:
11 (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9) = 11 x 45