A  man travelled 3/5 of his journey by train, 1/4 by a taxi , 1/8 by a bus and the remaining 8 km on foot. what is the total length of his journey

  Let the total length of his journey be n.

 So,

       Distance travelled by him by train = 3n

                                                                        5

        Distance travelled by him by taxi = n

                                                                      4

        Distance travelled by him by bus = n

                                                                       8

         Distance travelled by him on foot = remaining 8km

 So, equation =

      n - [ 3n + n +n ] = 8

              5      4    8

=> n - [ 3n + 2n + n ] = 8

              5          8

=> n - [ 3n + 3n ] = 8

              5       8

=> n - [ 24n + 15n ] = 8

                    40

=> n - 39n = 8

            40

=> 40n - 39 = 8

           40

=>  n  = 8                              next, we will do cross-multiplication

     40

=> n = 8 x 40

=> n = 320

 Therefore, the total distance travelled by him is 320km.