Two persons starting from the same place walk at a rate of 5kmph and 5.5kmph respectively. What time will they take to be 8.5km apart, if they walk in the same direction?
A. 17 hrs
B. 22 hrs
C. 25 hrs
D. 12 hrs
Answers
Answered by
1
By verifying using option at 17 hrs
5×17=85 and 5.5×17=93.5
Difference in distance is 8.5km at 17hrs
So option is 17hrs
5×17=85 and 5.5×17=93.5
Difference in distance is 8.5km at 17hrs
So option is 17hrs
Answered by
1
A =====================B
here we can use the concept of relative ,
if both are same direction , and let V1 and V2 are velocity of both then ,
relative velocity of 2ndwith respect to 1st = V2 -V1 =(5.5 -5) = 0.5km/h
now, time = relative distance/relative velocity
because they moves in same place so , relative distance = distance between final and initial point .
so, time = 8.5 km/0.5km/h
= 17 hours
so, option A is correct .
here we can use the concept of relative ,
if both are same direction , and let V1 and V2 are velocity of both then ,
relative velocity of 2ndwith respect to 1st = V2 -V1 =(5.5 -5) = 0.5km/h
now, time = relative distance/relative velocity
because they moves in same place so , relative distance = distance between final and initial point .
so, time = 8.5 km/0.5km/h
= 17 hours
so, option A is correct .
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