Question

Julie drives 100 mi to Grandmother's house. On the way to Grandmother's, Julie drives half the distance at 44.0mph and half the distance at 65.0 . On her return trip, she drives half the time at 44.0mph and half the time at 65.0mph .
1)What is Julie's average speed on the way to Grandmother's house?

2)What is her average speed on the return trip?



*Express your answer with the appropriate units.

Answer 1

Answer:

52.47706 mph

54.5 mph

Explanation:

The average speed is given by

$V_{av}=\dfrac{Distance}{Time}$

$V_{av}=\dfrac{100}{\dfrac{50}{44}+\dfrac{50}{65}}\\\Rightarrow V_{av}=52.47706\ mph$

Julie's average speed on the way to Grandmother's house is 52.47706 mph

$V_{av}=\dfrac{44+65}{2}\\\Rightarrow V_{av}=54.5\ mph$

Average speed on the return trip is 54.5 mph