Malcolm wants to visit Isabella after school today and knows the street where she lives but doesn't know her house number. She tells him, "My house number has two digits, and exactly three of the following four statements about it are true."
(1) Its digits are identical.
(2) Its digits sum to an odd number.
(3) It is a multiple of 3.
(4) It is less than 50.
This information allows Malcolm to determine Isabella's house number. What is its units digit?
1
2
3
4
5
