Savita left her home at 11a.m.,travelling along route 1 at 30kmph.At 1.p.m.,her brother rohan left home and started after her on the same road at 45 kmph. At what time did Rohan catch up to Savita?
Notice that the distance Savita covered is equal to that of Rohan that is, distance is constant. Letting x equal Savita's time, Rohans time is x 2.
Speed x time = distance
Savita: (30) (x) = 30x
Rohan: (45) (x 2) = 45x 90
Because the distance is constant, so, we have:
30x = 45x 90
15x = 90
x = 6Savita had travelled 6 hours when Rohan caught up with her. Because Savita left at 11 a.m., Rohan caught her up at 5:00 p.m.