posted by berha on .
Sally travels by car from one city to another. She drives for 24.0 min at 63.0 km/h, 36.0 min at 45.0 km/h, and 44.0 min at 49.0 km/h, and she spends 13.0 min eating lunch and buying gas.
Is the question average speed?
Assuming average speed, you must find total distance, then total time, then divide them
Time is easy: 24 + 36 + 44 + 13 minutes
So how far do you get driving 24.0 min at 63.0 km/h? 36.0 min at 45.0 km/h? 44.0 min at 49.0 km/h?
60 min at 63 kph would bring you 63 km, so 24 min at 63 kph will bring you (24 / 60) * 63 km = 25.2 km
Then do the same for the other distances, and divide your total distance by total time