Let a table = 1 unit. Each chair is 1 unit − $15, so 9 chairs = 9 units − 9 × $15. With 3 tables that is 12 units − $135 = $360.<br><br>[[model:questions/solutions/q4150.png]]<br><br>• 3 tables + 9 chairs = 12 units, − 9 × $15 = $135 → $360<br>• 12 units → $360 + $135 = $495<br>• 1 unit (table) → $495 ÷ 12 = $41.25<br>• 1 chair → $41.25 − $15 = $26.25<br>• 2 chairs → 2 × $26.25 = $52.50<br><br>The cost of the two chairs is $52.50.<br>Check: 3($41.25) + 9($26.25) = $123.75 + $236.25 = $360. ✓