Question 818584:  A chainsaw requires 3 hours of assembly and a wood chipper 5 hours. A maximum of 30 hours of assembly time is available. The profit is $130 on a chainsaw and $180 on a wood chipper. How many of each should be assembled to maximize profit?
 
I am not even sure where to start! 
 Answer by TimothyLamb(4379)      (Show Source): 
You can  put this solution on YOUR website! saw:  
number produced: s 
time to assemble: 3 hrs/unit 
profit: 130 $/unit 
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chipper:  
number produced: c 
time to assemble: 5 hrs/unit 
profit: 180 $/unit 
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3s + 5c = 30 
3s = 30 - 5c 
s = 10 - (5/3)c 
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130s + 180c = p 
130(10 - (5/3)c) + 180c = p 
1300 - (650/3)c + 180c = p 
1300 - (650/3)c + (540/3)c = p 
1300 - (110/3)c = p 
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profit turns out to be a linear function of the number of chippers produced ! 
p(c) = (-110/3)c + 1300 
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use the slope-intercept form of the linear equation: 
slope = (-110/3) = -36.666666 
y-intercept = 1300 
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plug this (the slope and y-intercept): 
-36.666666 1300 
into the "Slope–Intercept form: m b" input box here: 
https://sooeet.com/math/linear-equation-solver.php 
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x-intercept = 35.45 
y-intercept = 1300 
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answer: 
profit is maximized at $1300 when zero chippers are produced, and profits go to zero when 35 chippers are produced. 
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if zero chippers are produced, 10 saws are produced: 
3s + 5c = 30 
3s + 5(0) = 30 
3s = 30 
s = 10 
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check: 
profit when 10 saws are produced: (10 saw units) * (130 $/unit) = $1300 (correct) 
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