A train covered a certain distance at a uniform speed. If the train had been 6 km/hr faster, it would have taken 4 hour less than the scheduled time. And, if the train were slower by 6 km/hr, the train would have taken 6 hr more than the scheduled time. The length of the journey is:
Choose the most appropriate option.
A) 720 km	B) 700 km	C) 740 km	D) 600 km	E) None of these
Explanation :   Let the length of the journey be d km and the speed of train be S km/hr.   Then,   =&gt;d/(S+6)=t−4. ---------------(i)   =&gt;d/(S−6)=t+6. ---------------(ii)   Subtracting the (i) equation from(ii), we get :-   =&gt;d/(S−6)−d/(S+6)=10 --------------(iii)   Since, Time=Distance/Speed.   From (i) , (ii) and (iii), w get :-   S=30 and d = 720 km.   720 kmnswer : 720 km
<result>A</result>
A train covered a certain distance at a uniform speed. If the train had been 6 km/hr faster, it would have taken 4 hour less than the scheduled time. And, if the train were slower by 6 km/hr, the train would have taken 6 hr more than the scheduled time. The length of the journey is: