Tue January 29, 2013 By:

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?

Expert Reply
Wed January 30, 2013

Notice that the distance Savita covered is equal to that of Rohan that is, distance is constant. Letting x equal Savita's time, Rohan’s 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 = 6

Savita 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.
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