Transcript Section 2.3 - Shelton State Community College

Section 2.3
Applications of Linear Equations
Before Rudy and Theo…
http://youtu.be/lPGT_ZMs_Cc
A Problem Solving Algorithm
1. Read the problem.
2. Read the problem.
3. Read the problem. Determine what you are
being asked to find.
Continued…
4. Assign variables:
a. If the problem deals with a geometric
figure (triangle, rectangle), draw a picture
b. If the problem deals with mixtures or
investments, make a chart
c. If all else fails, try “let x =“
Continued.
5. Write and solve your equation.
6. Answer the question in the context of the
problem.
7. Make sure your answer is reasonable.
More about geometry
• The formula for perimeter of a rectangle is
P = 2L + 2W
• The formula for perimeter of a triangle is
P=a+b+c
Geometry
1. The top floor of the John Hancock Center is
rectangular and has perimeter 520 ft. The
width of the top floor measures 20 ft more
than one-half its length. What are the
dimensions of the top floor?
Geometry
2. The Vietnam Veterans Memorial in
Washington, DC, is in the shape of two sides
of an isosceles triangle. If the two walls of
equal length were joined by a straight line of
438 ft, the perimeter of the resulting triangle
would be 931.5 ft. Find the length of the two
walls.
Find The Number
3. Ted Williams and Rogers Hornsby were two
great hitters in Major League Baseball.
Together, they got 5584 hits in their careers.
Hornsby got 276 more hits than Williams.
How many base hits did each get?
Percentage
4. Composite scores on the ACT exam rose from 20.8 in 2002 to
21.1 in 2009. What percent increase was this, to the nearest
tenth of a percent?
5. In 1995, the average cost of tuition and fees at private fouryear universities in the United States was $12,216 for fulltime students. By 2009 it had risen approximately 115.1%. To
the nearest dollar, what was the approximate cost in 2009?
6. David Ruppel sold his house for $159,000. He got this
amount knowing that he would have to pay a 6%
commission to his agent. What amount did he have after the
agent was paid?
More about mixture and investment
problems
The first
column is
your unit
prices or
your
percentages
The second
column is the
quantities or
dollar
amounts
The third column is always
the product of the first and
second columns. Your
equation comes from this
column.
Investment
7. Sheryl Zavertnik won $60,000 on a slot machine in
Las Vegas. She invested part of the money at 2%
simple interest and the rest at 3%. In one year, she
earned a total of $1600 in interest. How much was
invested at each rate?
8. Piotr Galkowski invested some money at 3.5%
simple interest, and $5000 more than three times
this amount at 4%. He earned $1440 in annual
interest. How much did he invest at each rate?
Mixture
9. How many liters of a 10% alcohol solution
must be mixed with 40 L of a 50% solution to
get a 40% solution?
10.Lee Ann Spahr wants to mix tea worth 2
cents per oz with 100 oz of tea worth 5 cents
per oz to make a mixture worth 3 cents per
oz. How much 2 cent tea should be used?