Answer
34 Km
Step-by-step explanation
Assuming that the dog ran x Km the first day,
1st day = x km
2nd day = (x+2)
3rd day = (x+2)+2 = (x+4) Km
So we have,
x + (x+2) + (x+4) = 54
3x + 6 =54
3x = 54-6
3x = 48
x = 16 Km.
∴
1st day = 16 Km
2nd day = 16 + 2 = 18
Total distance for the first 2 days = 16 + 18 = 34 Km