Question

please solve question very fast if you're able

Answer 1

let force applied by each man is F
if 2F gives no acceleration that means frictional force =applied force
if 3F applied 0.2 acceleration
f-2F=0
f=2F
2F=M(0)
3F=M(0.2)
F=0.2(M)
if 5F act 2F go for frictional force
and other 3Fis 3(.2)=0.6