Answer: Complete Solution: A smile is worth \$15. A frown is worth \$10, and a neutral face is worth \$12. There are many ways to approach this challenge. Top row (2 smiles and 1 frown) = \$40 Middle column (2 smiles and 2 frowns) = \$50 The middle column has one more frown and costs \$10 more than the top row, so: 1 frown = \$10 Since 2 smiles and 1 frown = \$40 and 1 frown = \$10, Subtracting 2 smiles = \$30, so that 1 smile = \$15 Alternate Solution: Another way is to use the first and third rows: Top row (2 smiles and 1 frown) = \$40 Third row (1 smile and 2 frowns) = \$35 Continue the pattern, lose a smile, and add a frown for \$5 less: 0 smiles and 3 frowns = \$30 1 frown = \$10 Then continue the first method to find the cost of a smile.
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