Algebraic Number Sequence Puzzle

48

Explanation:
A) 124 + 0 = 15
20 - (1+4)

B) 246 + 0 = 32
40 - (2+6)

C) 357 + 0 = 40
50 - (3+7)

Then
468 + 0 = 48
60 - (4+8)