3 bags of chips and 5 bottles of water cost $31. A chip costs one dollar less than 3 bottles of water. Find the cost of each.
3 c + 5 b = 31
c = 3 b - 1
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3 (3b-1) + 5 b = 31
9 b - 3 + 5 b = 31
14 b = 34
c = 3 b - 1
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3 (3b-1) + 5 b = 31
9 b - 3 + 5 b = 31
14 b = 34