A train secured a separation at a uniform velocity. On the off chance that the train had been 6 km/hr speedier, it would have taken 4 hours not exactly the booked time, and if the train were slower by 6 km/hr, the train would have taken 6 hours more than the planned time. The length of the trip is?
Select one:
a. – 740 km
b. 700 km
c. 720 km
d. – 760 km