Question 514292
Let
Car A Speed = a km/h
Car B Speed = a/2 km/h
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Car A will travel total distance in 5 hours = a * 5 = 5a km
Car B will travel total distance in 5 hours = a/2 * 5 = 5a/2 km

They are traveling in oppisite directions so 
sum of the distance travelled by both Cars = 600km

5a+5a/2=600
(10a+5a)/2=600
15a/2=600
15a=600*2
15a=1200
a=1200/15
a=80

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Car A Speed = a=80 km/h
Car B Speed = a/2=80/2=40 km/h
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Check

Distance travelled by Car A = 80 * 5 = 400 km
Distance travelled by Car B = 40*5 = 200km
Total Distance b/w Car A and B = 400+200 = 600 km