A car travels 50 km/h for 30 min, 40 km/h for next 15 min and then 60 km/h for another 1 hour. Calculate the average speed of the car.

Use the formula Distance=Rate*Time

Luchia's formula will enable you to calculate the distance of each portion of the trip. Then you just need to remember that

avg_speed = total_distance/total_time

To calculate the average speed of the car, we need to find the total distance traveled and the total time taken.

First, let's calculate the distance traveled at each speed:

Distance1 = Speed1 * Time1
Distance1 = 50 km/h * (30 min / 60 min/h)
Distance1 = 50 km/h * 0.5 h
Distance1 = 25 km

Distance2 = Speed2 * Time2
Distance2 = 40 km/h * (15 min / 60 min/h)
Distance2 = 40 km/h * 0.25 h
Distance2 = 10 km

Distance3 = Speed3 * Time3
Distance3 = 60 km/h * 1 h
Distance3 = 60 km

Now, let's calculate the total distance:

Total Distance = Distance1 + Distance2 + Distance3
Total Distance = 25 km + 10 km + 60 km
Total Distance = 95 km

Next, we need to calculate the total time taken in hours:

Total Time = Time1 + Time2 + Time3
Total Time = 30 min + 15 min + 1 hour
Total Time = 0.5 hour + 0.25 hour + 1 hour
Total Time = 1.75 hours

Finally, we can calculate the average speed:

Average Speed = Total Distance / Total Time
Average Speed = 95 km / 1.75 hours
Average Speed ≈ 54.29 km/h

Therefore, the average speed of the car is approximately 54.29 km/h.