Walking at 7/8 of its usual speed, a train is 10 minutes too late. Find its usual time to cover the journey.
90 min
70 min
50 min
40 min
60 min
Initial Final
Speed 8 7
Time 7 8
Time increased = 1unit => 10 minutes
Usual Time (7 units) = 10 x 7 => 70 minutes