一桶油连桶重55.1千克，用去一半后连桶重30.1千克，这桶油重多少千克？桶重多少千克？+K3I5Y+S1p/I0['Q;h:E2o
算式：提示'V0v*[+D3N4I)R.a+K3I5Y+S1p/I0['Q;h:E2o
这桶油重,M2l0\*i(^(f千克，桶重.f0^:l.b2b3D2y3g5V千克。+K3I5Y+S1p/I0['Q;h:E2o