A car traveled at 50km/h for 4 hours and at 60km/h for 3 1/2 hours. What was the average speed for the whole journey?
distance of first leg = 4(50 ) = 200 km
distance of 2nd leg = 3.5(60) = 210 km
avg speed = total distance/total time
= 410/7.5 = appr 54.7 km/h
To find the average speed for the whole journey, we need to determine the total distance traveled and the total time taken.
First, let's calculate the distance traveled during the first part of the journey, where the car traveled at 50km/h for 4 hours:
Distance = Speed × Time
Distance = 50km/h × 4 hours
Distance = 200km
Next, let's calculate the distance traveled during the second part of the journey, where the car traveled at 60km/h for 3 1/2 hours:
Distance = Speed × Time
Distance = 60km/h × 3.5 hours
Distance = 210km
Now, let's determine the total distance traveled by adding the distances of both parts of the journey:
Total Distance = 200km + 210km
Total Distance = 410km
To find the average speed, we need to divide the total distance by the total time taken. The total time can be found by adding the individual times of both parts of the journey:
Total Time = 4 hours + 3.5 hours
Total Time = 7.5 hours
Finally, let's calculate the average speed:
Average Speed = Total Distance ÷ Total Time
Average Speed = 410km ÷ 7.5 hours
Average Speed ≈ 54.67 km/h
Therefore, the average speed for the whole journey is approximately 54.67 km/h.