Yang 150N sama 4 bukan?

Lk/Lb = W/F
2,5m/0,5m = 600/F
0,5 × 600 = 2,5F
300 = 2,5F
300/2,5 = F
120 N = F

KM = W/F = Lk/Lb
KM = 600/120 = 5 (jawabannya c)