Question 1000938
A coffee stand sells a total of 90 large and medium coffees. Large coffees sold for 3.00 and medium sold for 2.00. How many large and medium coffees did the stand sell if a total of 210.00 was earned 
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Quantity Eq: L + M = 90 cups
Value Eq::  3L + 2M = 210 dollars
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Modify for elimination::
2L + 2M = 2*90
3L + 2M = 210
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Subtract and solve for "L"::
L = 30 (# of large cups sold)
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Solve for "M"::
30 + M = 90
M = 60 cups (# of medium cups sold)
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Cheers,
Stan H.
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