1). 20 min.2). 15.5 min.3). 10.5 min.4). 7.5 min.

1.	1). 20 min.2). 15.5 min.3). 10.5 min.4). 7.5 min.
Answer» In a 3000 m race AROUND a field having the circumference of 600 m, the top runner meets the last runner on the 5^th minute of the race and the top runner runs at twice the speed of the last runner. So, the relative DISTANCE between the top runner and last runner = 600 m We know that, Speed = Distance/TIME And relative speed (Top runner’s speed - last runner’s speed) = (600/5) m/min = 120 m/min If the top runner’s speed is twice the speed of the last runner, then Top runner’s speed = 2 × last runner’s speed. So, (2 × last runner’s speed) - (last runner’s speed) = 120 m/min ⇒ Last runner’s speed = 120 m/min The speed of top runner = 120 × 2 = 240 m/min Time taken by top runner to FINISH the race = 3000/240 = 12.5 min ∴ Time taken by top runner to finish the race = 12.5 min

Answer»

In a 3000 m race AROUND a field having the circumference of 600 m, the top runner meets the last runner on the 5^th minute of the race and the top runner runs at twice the speed of the last runner. So, the relative DISTANCE between the top runner and last runner = 600 m

We know that,

Speed = Distance/TIME

And relative speed (Top runner’s speed - last runner’s speed) = (600/5) m/min = 120 m/min

If the top runner’s speed is twice the speed of the last runner, then Top runner’s speed = 2 × last runner’s speed.

So, (2 × last runner’s speed) - (last runner’s speed) = 120 m/min

⇒ Last runner’s speed = 120 m/min

The speed of top runner = 120 × 2 = 240 m/min

Time taken by top runner to FINISH the race = 3000/240 = 12.5 min

∴ Time taken by top runner to finish the race = 12.5 min

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