Question

A person travels by car from one city to another with different constant speeds between pair of cities. She drives for 36 min at 80.5 km/h, 10 min at 92.7 km/h, and 54.3 min at 35.6 km/h, and spends 20.9 min eating lunch and buying gas. Find the distance between the initial and final cities along this route. Answer in units of km

Answer 1

Change minutes to hrs, divide by 60:
30 min = .50 hrs
45 min = .75 hrs
12 min = .20 hrs
----------------
total + 1.45 hrs, total travel time
:

let a = average speed for the trip
:
Write a dist equation, dist = speed * time
:
80(.5) + 100(.20) + 40(.75) = 1.45a
40 + 20 + 30 = 1.45a
90 = 1.45a
a =
a = 62.069 km/h, for the entire trip
and
90 km is the total distance