SOLUTION: Linear systems word problem: "The cost of six pennants and nine balls is $48. The cost of three balls is $1 more than the cost of one pennant. What are the costs of one pennant an

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Linear systems word problem: "The cost of six pennants and nine balls is $48. The cost of three balls is $1 more than the cost of one pennant. What are the costs of one pennant an      Log On


   



Question 701258: Linear systems word problem:
"The cost of six pennants and nine balls is $48. The cost of three balls is $1 more than the cost of one pennant. What are the costs of one pennant and one ball?"
I need help writing two equations and can it be solved using elimination? If not,can you solve it for me using substitution? Thanks!

Found 2 solutions by MathLover1, stanbon:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let the cost of pennants be x and the cost of balls y:
if the cost of six pennants and nine balls is $48 we can write it as
6x%2B9y=48......eq. 1

if the cost of three balls is $1 more than the cost of one pennant, than we write it as
3y=x%2B1....eq. 2
now we have system to solve:
6x%2B9y=48......eq. 1
3y=x%2B1....eq. 2
__________________________
start with 3y=x%2B1....eq. 2 and solve for y
y=%28x%2B1%29%2F3.....substitute it in eq. 1
6x%2B9%28x%2B1%29%2F3=48......solve for x
6x%2Bcross%289%293%28x%2B1%29%2Fcross%283%29=48
6x%2B3%28x%2B1%29=48
6x%2B3x%2B3=48
9x=48-3
9x=45
x=45%2F9
highlight%28x=5%29....the cost of pennants
now find y
y=%285%2B1%29%2F3
y=6%2F3
highlight%28y=2%29......the cost of balls



Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The cost of six pennants and nine balls is $48. The cost of three balls is $1 more than the cost of one pennant. What are the costs of one pennant and one ball?"
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Value Equations:
6p + 9b = 48
3b = p + 1
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Substitution:
p = 3b-1
Substitute for "p" and solve for "b":
6(3b-1) + 9b = 48
18b - 6 + 9b = 48
27b = 54
b = $2.00 (cost of 1 ball)
---
Solve for "p":
p = 3b-1
p = 3*2-1
p = $5.00 (cost of one pennant)
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Elimination:
6p + 9b = 48
3b = p + 1
---
Rearrange
3b + 2p = 16
3b - p = 1
---
Subtract and solve for "p"
3p = 15
p = $5.00 (pennant)
Solve for "b":
3b - p = 1
3b - 5 = 1
3b = 6
b = $2.00 (ball)
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Cheers,
Stan H.
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