Transcript Warm-up - Leavenworth High School

Writing Systems of
Equations
Example 1
The admission fee at a small fair is $1.50 for children
and $4.00 for adults. On a certain day, 2200 people
enter the fair and $5050 is collected. How many
children and how many adults attended?
Children = c
Adults = a
•Step 1: Assign variables.
The question tells you what
you are looking for.
$ Eqn: 1.5c + 4a = 5050 • Step 2: Write equations,
using your variables, and the
People
c + a = 2200
information from the
Eqn:
paragraph. Should have two
equations.
Example 1 - Continued
1) 1.5c + 4a = 5050
2) -4( c + a = 2200) -4
● Step 3 : Solve your
system for what they are
asking for.
1) 1.5c + 4a = 5050
2)+___________
-4c – 4a = -8800 +
- 2.5c = -3750
● Step 4: Make sure your
-2.5
-2.5
answers make SENSE!
c = 1500
Ex: There CANNOT be 1.5
1500 Children
of a person !
Example 1 - Continued
1) 1.5c + 4a = 5050
2)
c + a = 2200
1500 + a = 2200
-1500
- 1500
a = 700
700 Adults
1500 Children
c = 1500
Example 2
Brenda and Castel are selling wrapping paper for a school
fundraiser. Customers can buy rolls of plain wrapping paper
and rolls of shiny wrapping paper. Brenda sold 12 rolls of plain
wrapping paper and 11 rolls of shiny wrapping paper for a total
of $248. Castel sold 9 rolls of plain wrapping paper and 5 rolls
of shiny wrapping paper for a total of $134. What is the cost of
one roll of plain wrapping paper?
Cost of 1 roll of plain = p
Cost of 1 roll of shiny = s
Brenda: 12p + 11s = 248
Castel:
9p + 5s = 134
•Step 1: Assign variables. The
question tells you what you are
looking for.
• Step 2: Write equations, using
your variables, and the
information from the paragraph.
Should have two equations.
Example 2 - Continued
1) 5( 12p + 11s = 248 ) 5
2)-11(9p + 5s = 134 ) -11
● Step 3 : Solve your
system for what they are
asking for.
• Only need PLAIN! So
eliminate shiny!
1) 60p + 55s = 1240
2)+_____________
-99p – 55s = -1474 +
- 39p = -234
● Step 4: Make sure your
-39
-39
answers make SENSE!
p=6
$6 for cost of plain paper
Example 3
On the day of the field trip, each teacher must call the parents of
any student who has not returned a permission slip. All of Mr.
Gomez's students returned their permission slips, so he did not
have to make any calls. Mrs. Hooper and Mr. Anderson had to
call a total of eight parents. Mrs. Hooper needed to call two more
students than Mr. Anderson. How many phone calls did Mr.
Anderson make?
Calls for Mr. Anderson = a
Calls for Mrs. Hooper = h
Total
h + a=8
calls:
Hooper: h = a + 2
•Step 1: Assign variables. The
question tells you what you are
looking for.
• Step 2: Write equations, using
your variables, and the
information from the paragraph.
Should have two equations.
Example 3 - Continued
1)
2)
h + a = 8
h= a +2
● Step 3 : Solve your
system for what they are
asking for.
a+2+a=8
2a + 2 = 8
-2 _-2
2a = 6
2
2
a=3
● Step 4: Make sure your
answers make SENSE!
Mr. Anderson made 3 calls
Homework
Writing Systems
Worksheet