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Question
Salman and Kirti start at the same time from two places 28 km apart. If they walk in the same direction, Salman overtakes Kirti in 28 hours but if they walk in the opposite directions, they meet in 4 hours. Find their speeds (in km/h).
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Solution
Let the speed of Salman = x km/hr
and the speed of Kirti = y km/hr
Total distance = 28 km
When they walk in the same direction,
28x - 28y = 28
⇒ x - y = 1 ....(i)
When they walk in the opposite direction,
4x + 4y = 28
⇒ x + y = 7 ....(ii)
Adding eqns. (i) and (ii), we get
2x = 8
⇒ x = 4
⇒ 4 + y = 7
⇒ y = 3
Thus, the speed of Salman is 4 km/hr and that of Kirti is 3 km/hr.
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