Which one will replace the question mark?

For first triangle,

10 - 4 = 6

18 - 10 = 8

18 - 4 = 14

For second triangle,

14 - 8 = 6

22 - 14 = 8

22 - 8 = 14

For third triangle,

11 - 5 = 6

15 - 11 = 4

15 - 5 = 10.