Draw a bar model: each chair = 1 unit, each stool = 1 unit - $10.
4 chairs + 3 stools = 4u + 3(u - $10) = 7u - $30 = $173.
7u = $203, 1 unit = $29. Stool = $29 - $10 = $19.
AGS Rule Box
Cost relation=Stool = Chair - $10
4 chairs + 3 stools=4u + 3(u - 10) = 7u - 30 = $173
7 units=$173 + $30 = $203
1 unit (chair)=$203 / 7 = $29
1 stool=$29 - $10 = $19
Final Answer: 19