Download 7.4 Applications of Systems

7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
7.4 Applications of Linear Systems
1. Anthony and Anne bought some pens and pencils.
Anthony bought 4 pens and 5 pencils, which cost him $6.71.
Anne bought 5 pens and 3 pencils, which cost her $7.12.
Let x equal the price of a pen. Let y equal the price of a pencil.
a. Write an equation that relates the
number of pens and pencils Anthony
bought to the amount he paid for them.
b. Write an equation that relates the number
of pens and pencils Anne bought to the
amount she paid for them.
c. Solve the system you wrote for
parts (a) and (b) to find the price
of a pen and the price of a pencil.
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
2. Suppose you bought supplies for a party. Three rolls of streamers
and 15 party hats cost $30. Later, you bought 2 rolls of streamers and
4 party hats for $11. How much did each roll of streamers cost?
How much did each party hat cost?
x=
y=
2
7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
2. Suppose you bought supplies for a party. Three rolls of streamers
and 15 party hats cost $30. Later, you bought 2 rolls of streamers and
4 party hats for $11. How much did each roll of streamers cost?
How much did each party hat cost?
streamers
hats
Answer
streamers cost $2.50
hats cost $1.50
3x+22.5 = 30
­22.5 ­22.5
3x=7.5
3 3
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
3. The Math Club and the Science Club had fundraisers to buy supplies
for a local food pantry. The math club spent $135 buying six cases of
juice and one case of bottled water. The science club spent $110 buying
four cases of juice and two cases of bottled water. How much did a
case of juice cost? How much did a case of bottled water cost?
x=
y=
Answer
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
3. The Math Club and the Science Club had fundraisers to buy supplies
for a local food pantry. The math club spent $135 buying six cases of
juice and one case of bottled water. The science club spent $110 buying
four cases of juice and two cases of bottled water. How much did a
case of juice cost? How much did a case of bottled water cost?
x=juice
y=water
Answer
juice costs
water costs
4x=80
4 4
x=20
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
4. Suppose you bought supplies for a party. Three rolls of streamers
and 14 party hats cost $40. Later, you bought 2 rolls of streamers
and 4 party hats for $16. How much did each roll of streamers cost?
How much did each party hat cost?
x=
y=
streamers cost
hats cost
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
4. Suppose you bought supplies for a party. Three rolls of streamers
and 14 party hats cost $40. Later, you bought 2 rolls of streamers
and 4 party hats for $16. How much did each roll of streamers cost?
How much did each party hat cost?
x=
y=
streamers cost
hats cost
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
9. The sum of two numbers is 32. Their difference is 8.
Write a system of equations that describes this situation
and then solve to find the two numbers.
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
9. The sum of two numbers is 32. Their difference is 8.
Write a system of equations that describes this situation
and then solve to find the two numbers.
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
10. The sum of two numbers is 50. Their difference is 20.
Write a system of equations that describes this situation
and then solve to find the two numbers.
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
10. The sum of two numbers is 50. Their difference is 20.
Write a system of equations that describes this situation
and then solve to find the two numbers.
y= 2nd number
option 1 for how to write answer
The first number is 35
the second number is 15
2x = 70
2 2 x = 35
x + y = 50
35 + y = 50
­35 ­35 y = 15
option 2 for how to write answer
The numbers are 35 and 15
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7.4 Applications of Systems ­ word prb.notebook
February 01, 2013
Homework: Complete HW sheet problems #1­4 and #8­10 Show work like we did in the notes. Do the work in your notebook or on looseleaf.
Your choice.
Bring HW back on Monday to show me.
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