Introduction to Distance-Rate-Time Applications

Example 1:

Jan drives south out of Denver and averages 65mph. How far is she from Denver after 3 hours.

Use the formula …

d r t

distance = rate × time

65 3 195

Jan drove 195 miles.

Introduction to Distance-Rate-Time Applications

Example 2:

Write an expression for the distance traveled if the average rate is r mph and the time is 6 hours.

Use the formula …

d r t

distance = rate × time

6r 6r

The distance is given by 6r.

A plane flies p mph in a wind that is 30 mph. Write expressions for the ground speed of the plane going:

1) With the wind

2) Against the wind

Introduction to Distance-Rate-Time Applications

Example 3:

1) Going with the wind, the planes ground speed is increased! The wind is helping the plane to fly at an increased rate.

ground rate = (rate of plane) + (rate of wind)

r p w

2) Going against the wind, the planes ground speed is decreased! The wind is causing the plane to fly at an slower rate.

ground rate = (rate of plane) - (rate of wind)

r p w