Answer: 2 lbs of cherries
Cherries = $5 per pound
Oranges = $2 per pound
Total Cost = $18
Total weight = 6 lb
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Define x and y
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Let x be the number of lb of cherries
Let y be the number of lb of oranges
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Construct equations
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x + y = 6 ---------------------------- (1)
5x + 2y = 18 ---------------------------- (2)
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Solve x and y
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From equation (1):
x + y = 6
x = 6 - y
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Substitute x = 6 - y into equation 2
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5x + 2y = 18
5 (6 - y) + 2y = 18
30 - 5y + 2y = 18
3y = 30 - 18
3y = 12
y = 4
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Substitute y = 4 into equation (1)
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x + y = 6
x + 4 = 6
x = 2
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Find the weight of cherries and oranges
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Cherry = x = 2 lb
Oranges = y = 4 lbs
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Answer: Alex bought 2 lb of cherries
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