With an average speed of 40km/hr. a train reached its destination in time. If it goes whith an average speed of 35km/hr, it is late by 15 minute . The total journey is ?
30 km
40 km
70 km
80 km
Correct Option: C
Let total journey be y km. From question y/35 - y/40= 15/60 ⇒ y = ( 35 x 40 )/ ( 4 x 5 ) = 70 ∴ Total Journey = 70 km