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/5+n/4+n/8 ] = 8
=> n - [ (24n + 15n)/40 ] = 8
=> n - 39n/40 = 8
=> 40n -39n = 8 x 40
=> n = 8 x 40
=> n = 320
Therefore, the total distance travelled by him is 320km.