Algebra Demystified 2nd Ed

Chapter 11 QuaDraTiC appliCaTionS 437

() 40 () 30 10

1600 900 100

2500 100

1

222

22

2

2

tt

tt

t

t

+=

+=

=

=^000

2500

100

2500

10

50

1

5

t

t

=

==

After^15 of an hour (or 12 minutes) the car and train will be 10 miles
apart.

PRACTICE

1. A car and plane leave an airport at the same time. The car travels
   eastward at an average speed of 45 mph. The plane travels south-
   ward at an average speed 200 mph. When will they be 164 miles
   apart?


2. Two joggers begin jogging from the same point. One jogs south at the
   rate of 8 mph and the other jogs east at a rate of 6 mph. When will they
   be 5 miles apart?


3. A cross-country bicyclist crosses a railroad track just after a train passed.
   The train is traveling southward at an average speed of 60 mph. The
   bicyclist is traveling westward at an average speed of 11 mph. When will
   they be 244 miles apart?


4. A motor scooter and car left a parking lot at the same time. The motor
   scooter traveled north at 24 mph. The car traveled west at 45 mph. How
   long did it take for the scooter and car to be 34 miles apart?


5. Two cars pass each other at 4:00 at an overpass. One car is headed north
   at an average speed of 60 mph and the other is headed east at an aver-
   age speed of 50 mph. At what time will the cars be 104 miles apart? Give
   your solution to the nearest minute.

PRACTICE

1. A car and plane leave an airport at the same time. The car travels
   eastward at an average speed of 45 mph. The plane travels south-

PRACTICE

1. A car and plane leave an airport at the same time. The car travels