Sally travels by car from one city to another. She drives for 30.0 min at 52.0 km/h, 35.0 min at 48.0 km/h, and 23.0 min at 50.0 km/h, and she spends 10.0 min eating lunch and buying gas.
avg. speed= distance traveled / time of travel
The Attempt at a Solution
first, I added all three speeds (52+48+50) and divided by 3. I got 50 as the average speed, but the website says I'm incorrect.
How can I find the average speed without the distance traveled?
avg. speed = distance traveled / (30+35+23)
avg. speed = distance traveled / 88