Since both masses are same, let us represent mass by m.
For the suspended mass, ma=mg−T
For the mass on the table,
ma=T−μmg
Solving both the equations,
Acceleration is given by
a=g(1−μ)/2=10(1−0.2)/2=4m/s2
Tension is given by,
T=m(g−a)=20(10−4)=20×6=120N
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