6. Look at the factorizations of 36: (36,1,1), (18,2,1), (9,4,1),
(9,2,2), (6,6,1), (6,3,2), (4,3,3).  All these add to distinct
sums except 9+2+2 = 6+6+1 = 13.  That must be the first 2 digits
of the new family's license plate, or the neighbor would not have
needed more information.  The fact that the new family has an
_oldest_ daughter means the twins must be 2, not 6.  So, the
daughters are aged 9, 2, 2.