Ethanol is vaporized at 78 oc (hfg = 846 kj/kg) in a double-pipe parallel-flow heat exchanger at a rate of 0.04 kg/s by hot oil (cp = 2200 j/kg. k) that enters at 115 oc. if the heat transfer surface area and the overall heat transfer coefficients are 6.2 m2 and 210 w/m2.k, respectively, determine the outlet temperature and the mass flow rate of the oil using (a) the lmtd method and (b) the effectiveness method.