Two factory plants are making TV panels. Yesterday, Plant A produced 3000 fewer panels than Plant B did. Four percent of the panels from Plant A and 3% of the panels from Plant B were defective. How many panels did Plant A produce, if the two plants together produced 1070 defective panels?
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OpenStudy (mathstudent55):
The first step is to choose two variables to represent the numbers of panels made in each plant.
OpenStudy (anonymous):
A= b-3000
OpenStudy (mathstudent55):
Good.
You already have the two variables and the first equation.
OpenStudy (mathstudent55):
Now we need a second equation.
OpenStudy (mathstudent55):
How do you write 4% of A?
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OpenStudy (anonymous):
A.04
OpenStudy (mathstudent55):
0.04A
OpenStudy (anonymous):
a*.04
OpenStudy (anonymous):
oh okay
OpenStudy (mathstudent55):
Now do the same for 3% of B
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OpenStudy (anonymous):
B.03
OpenStudy (mathstudent55):
0.03B is better.
OpenStudy (anonymous):
yes
OpenStudy (mathstudent55):
The numbers of defective panels are 0.04A and 0.03B, right?
OpenStudy (anonymous):
yes
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OpenStudy (mathstudent55):
Now add them together and set the sum equal to 1070.
That's the second equation.
OpenStudy (anonymous):
.07=1070
OpenStudy (mathstudent55):
No.
0.04A and 0.03B are unlike terms. They can't be combined together.
Their sum must be written as 0.04A + 0.03B
OpenStudy (mathstudent55):
The second equation is:
0.04A + 0.03B = 1070
OpenStudy (anonymous):
correct
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OpenStudy (mathstudent55):
Now you have two equations:
A = B - 3000
0.04A + 0.03B = 1070
Now you need to solve the system of equations.
OpenStudy (mathstudent55):
Since the first equation is already solved for A, we can use substitution easily.
OpenStudy (mathstudent55):
Replace A of the second equation with B - 3000.
Then you will have an equation with only B, and you can solve it for B.
OpenStudy (anonymous):
.04A(b-3000)+.03=1070
OpenStudy (anonymous):
no
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OpenStudy (anonymous):
.04(b-3000)+.03=1070
OpenStudy (mathstudent55):
There is still a B with 0.03
OpenStudy (anonymous):
yes so 7b-120=1070?
OpenStudy (anonymous):
b=170
OpenStudy (anonymous):
.07
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