Answer: 5
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Work Shown
x = number of 250 gram cans
12-x = number of 500 gram cans
Those two expressions add to 12 cans total.
3x = cost of just the 250 gram cans only
5.50(12-x) = cost of the 500 gram cans only
3x + 5.50(12-x) = total cost of all cans, both types
3x + 5.50(12-x) = 48.50
3x + 66 - 5.50x = 48.50
-2.5x + 66 = 48.50
-2.5x = 48.50 - 66
-2.5x = -17.5
x = -17.5/(-2.5)
x = 7
Therefore, you have purchased 7 cans that are 250 grams each.
The remaining 12-x = 12-7 = 5 cans must be the 500 gram variety.
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Check:
7 small + 5 large = 12 cans total
7 small = 7*($3) = $21
5 large = 5*($5.50) = $27.50
total = $21 + $27.50 = $48.50
We have confirmed the answer is correct.