a car moves at a constant speed of 60 km/hr for 1 km and 40 km/hr for 1 km.what is average speed of car?
distance covered at first speed = 60 km
distance covered at 2nd speed = 40 km
total distance = 100 km
total distance = 2 hrs
avg speed = 100/2 = 50 km
ahhh, looks like we just have to average the speed.
Not so fast grasshopper, this was just coincidence
supposed the car went at 60 km for 2 hrs
and at 40 for 4 hrs
total distance = 120 + 160 pr 280 km
total time = 6 hrs
avg speed = 280/6 = appr 46.7 km/h
So, you can't just find the average of the speeds.