A train covers a certain distance in 35 minutes.  If its speed is reduced by 9 km/h, it takes 5 minutes more to cover the same distance.  The distance (in km.) is:

42

D = S × T           ⇒         D = S × \(\frac{35}{60}\) .... (i)

                                     D = S - 9 × \(\frac{40}{60}\) .... (ii)

S × \(\frac{35}{60}\) = (S - 9) × \(\frac{40}{60}\)

⇒ S = 72

⇒ D = 72 × \(\frac{35}{60}\) = 42 km