Hey there!!
Let's summarize the total cost for mountain bikes.
Materials - $60
Labor - $90
Let's take the number of mountain bikes as 'x'.
Total cost = 60x + 60x
... 120x
Let's summarize the total cost for trail bikes.
Labors - $60
Materials - $60
Let's take the total number of trail bikes as 'y'.
Total cost = 90y + 60y
... 150y.
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Total cost for materials = $2,400
Hence,
60x + 60y = 2,400
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Total cost for labor = $3,150
Hence,
90x + 60y = 3,150
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Now, we have 2 equations.
... 60x+60y = 2400
... 90x+60y = 3150
Now let's subtract both these equations.
... 30x = 3150-2400
... 30x = 750
... x = 750 / 30
... x = 250.
Hence, the number of mountain bikes the company plans to manufacture is 250.
Hope my answer helps!
