4.3 Applications of Systems of Linear
Equations
I CAN: Solve real world problems
using systems.
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EXAMPLE 1
A rectangular soccer field has perimeter
360 yd. Its length is 20 yd more than its
width. What are its dimensions?
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EXAMPLE 2
In recent Major League Baseball and National
Football League seasons, based on average ticket
prices, three baseball tickets and two football tickets
would have cost $159.50, while two baseball tickets
and one football ticket would have cost $89.66.
What were the average ticket prices for the tickets
for the two sports?
(Source: Team Marketing Report, Chicago.)
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EXAMPLE 3
A grocer has some $4-per-lb coffee as
some $8-per-lb coffee that she will mix
to make 50 lb of $5.60-per-lb coffee.
How many pounds of each should be
used?
Number of
Pounds
x
y
50
Price per
Pound
Value of
Coffee
4
8
4x
8y
280
5.60
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EXAMPLE 4
A train travels 600 mi in the same time
that a truck travels 520 mi. Find the
speed of each vehicle if the train’s
average speed is 8 mph faster than the
truck’s.
Distance
Rate
Time
Train
600
x+8
Truck
520
x
600
x8
520
x
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EXAMPLE 5
How many liters each of 15% acid and
33% acid should be mixed to get 120
liters of 21% acid?
Liters of
solution
x
y
120
% as a
decimal
.15
.33
.21
Liters of
pure acid
.15x
.33y
25.2
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HOMEWORK:
4.3 pg 259 #1,5,11,12,17,21,23,27,29
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