0 mph and half the distance at 69.0 mph . On her return trip, she drives half the time at 31.0 mph and half the time at 69.0 mph .

Part AWhat is Julie's average speed on the way to Grandmother's house?
Express your answer with the appropriate units.
Part BWhat is her average speed on the return trip?
Express your answer with the appropriate units.

a) v = 34.5 mph, b)   v = 50 mph

Explanation:

The average speed is defined.

             v = (x₂ -x₁) / (t₂ -t₁)

If the movement is with uniform speed we can also obtain the average speed, averaging the speeds with a time weight factor, if the time is equal for each speed

            v = (v₁ + v₂) / 2

a) For the outward journey

            v = (69.0 +0) / 2

            v = 34.5 mph

b) For the return trip

              v = (69.0 + 31.0) / 2

              v = 50 mph