Answer:10
Step-by-step explanation:The factors of 40 are: 1, 2, 4, 5, 8, 10, 20, 40
The factors of 110 are: 1, 2, 5, 10, 11, 22, 55, 110
The factors of 120 are: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120
Then the greatest common factor is 10.