Question 74264
A manufacturer builds racing bikes and mountain bikes, with the per unit manufacturing costs shown in table . The company has bugeted $15,900 for labor and $13,075 for materials .How many bicycles of each type can be built?

model     cost of materials      cost of labor

racing           $55                   $60
mountain         $70                   $90             
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Let r be # of racing bikes and m be # of mountain bikes:
60r+90m = 15900
55r+70m = 13075
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Rewrite to get smaller numbers:
2r + 3m = 530
11r+ 14m =2615
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Multiply 1st by 11 and 2nd by 2 to get:
22r + 33m =11*530
22r + 28m =2*2615
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Subtract 2nd from 1st to get:
5m = 600
m=120 (# of mountain bikes)
Substitute in 2r+3m = 530 to solve for "r":
2r+3*120 = 530
2r = 170
r = 85 (# of racing bikes)
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Cheers,
Stan H.