Distinguish between instantaneous speed and average speed. A man drives a car a distance of 200km at an average speed of 44kmh-1. What must be his average speed fot the next 220 km if he is to cover the total distances in 9 hours?
Divide 200 km by 44 kmh to determine the time it took to go that far. Subtract that from 9. That is the time remaining. Now, how fast must the driver go to travel 220 km in that remaining time? Divide 220 by the remaining time.
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Instantaneous speed refers to the speed of an object at a specific instant in time. It is the rate at which an object is moving at any given moment. On the other hand, average speed refers to the total distance traveled divided by the total time taken.
In the given scenario, the man drives a car a distance of 200 km at an average speed of 44 km/h. This means that it took him a certain amount of time to cover the 200 km, which can be calculated using the formula:
Time = Distance / Speed
Time = 200 km / 44 km/h = 4.54 hours (rounded to two decimal places)
Now, if the man wants to cover the remaining distance of 220 km in a total of 9 hours, we can calculate his required average speed using the formula:
Average Speed = Total Distance / Total Time
Total Distance = 200 km + 220 km = 420 km
Total Time = Total Time Available - Time Already Taken
Total Time = 9 hours - 4.54 hours = 4.46 hours (rounded to two decimal places)
Therefore, the required average speed for the next 220 km is:
Average Speed = 420 km / 4.46 hours ≈ 94.16 km/h (rounded to two decimal places)
Hence, the man must maintain an average speed of approximately 94.16 km/h for the next 220 km in order to cover the total distance in 9 hours.