Question 125762:  1)Photography reprints cost $0.52 each at a local photo shop. Through the mail, they cost $0.44 each plus $1.20 postage and handling. How many reprints must a customer purchase to make it less expensive to use mail order? 
 
2) 
 
 
Assume that the mathematical model C(x) = 16x + 130 represents the cost C, in hundreds of dollars, for a certain manufacturer to produce x items. How many items x can be manufactured while keeping costs between $525,000 and $781,000?  
 Found 2 solutions by  stanbon, checkley71: Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! 1)Photography reprints cost $0.52 each at a local photo shop. Through the mail, they cost $0.44 each plus $1.20 postage and handling. How many reprints must a customer purchase to make it less expensive to use mail order? 
Let "x" be number of reprints. 
INEQUALITY: 
mail order cost < local photo shop cost 
0.44x + 1.20 < 0.52x 
0.08x > 1.20 
x > 15 
mail order is less expensive if the number of prints is greater than 15 
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2)  
Assume that the mathematical model C(x) = 16x + 130 represents the cost C, in hundreds of dollars, for a certain manufacturer to produce x items. How many items x can be manufactured while keeping costs between $525,000 and $781,000?  
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525,000 < 16x+130 < 781,000 
32804.38 < x < 48804.38 
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Cheers, 
stan H. 
 Answer by checkley71(8403)      (Show Source): 
You can  put this solution on YOUR website! 1.20+.44*x<.52x 
.44x-.52x<-1.20 
-.08x<-1.20 
x>-1.20/-.08 here we have to change the < sign to the > sign because we have diiided by a negative number. 
x>15 photos by mail is the answer.  
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c(x)=16x+130 
5,250=16x+130 
16x=5,250-130 
16x=5,120 
x=5,120/16 
x=320 is the lower limit. 
7,810=16x+130 
16x=7,810-130 
16x=7,680 
x=7,680/16 
x=480 is the upper limit.
 
 
 
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