The exit temperature of the cold fluid is

Question

The LMTD of a counter flow heat exchanger is 20⁰C. the cold fluid enters at 20⁰C and the hot fluid enters at 100⁰C. mass flow rate of the cold fluid is twice that of the hot fluid. Specific heat at constant pressure of the fluid is twice that of the cold fluid. The exit temperature of the cold fluid is                            

      (a) 40⁰C                                                              (b) 60⁰C             

      (c) 80⁰C                                                              (d) can not be determined