Tom : Willy = 1 : 6 and Tom : Zack = 2 : 3. Make Tom the same in both ratios to combine.<br><br>[[model:questions/solutions/q4359.png]]<br><br>• Tom : Willy = 1 : 6 = 2 : 12<br>• Tom : Zack = 2 : 3<br>• Combined → Tom : Willy : Zack = 2 : 12 : 3<br>• Total units → 2 + 12 + 3 = 17u → 204 marbles<br>• 1u → 204 ÷ 17 = 12 ⇒ Tom = 2 × 12 = 24, Willy = 12 × 12 = 144, Zack = 3 × 12 = 36<br><br>Tom: 24, Willy: 144, Zack: 36<br>Check: 24 + 144 + 36 = 204. ✓