mohon bantuannya !!!

mB g - T = mB a
T - mA g sin θ = mA a
------------------------------ +
(mB - mA sin θ)g = (mB + mA)a
a = g(mB - mA sin θ) / (mA + mB)
   = (10 m/s²) [(3 kg) - (3 kg)(sin 30°)] / (3 kg + 3 kg) = 2,5 m/s²