The vapor-liquid equilibrium curve of a binary mixture A-B, may be approximated by a linear equation over a narrow range of liquid mole fractions ( 0.2 < xA < 0.3) as follows y*A = 1.325 xA + 0.121 Here y*A is the mole fraction of A in the vapor. 100 moles of a feed (xA, F = 0.28) is batch distilled to a final residue (xA, W = 0.2). Using the Rayleigh equation, the number of moles of the residue left behind in the distillation unit, up to 2 digits after the decimal point, is ____________