Algebra Demystified 2nd Ed

Chapter 11 QuaDraTiC appliCaTionS 441

()()24 45 34

576 2025 1156

2601 1156

222

22

2

2

tt

tt

t

t

+=

+=

=

==

=

=

=

1156

2601

4 9 4 9 2 3

t^2

t

t

The car and scooter will be 34 miles apart after^23 of an hour or 40 minutes.

5. Let t represent the number of hours after the cars passed the overpass.
   The northbound car’s distance after t hours is 60t and the eastbound
   car’s distance is 50t.

a = 60t c = 104

b = 50t

a^2 + b^2 = c^2

(60t)^2 + (50t)^2 = 104^2

FIGURE 11-10

()()

,

60 50 104

3600 2500 10 816

6100 10

222

22

2

tt

tt

t

+=

+=

= ,,

,

.

816

10 816

6100

2704

1525

2704

1525

133

2

2

t

t

t

t

=

=

=

≈

The cars will be 104 miles apart after about 1.33 hours or 1 hour 20 minutes.
The time will be about 5:20.