Mel = 4 × Zack. The model shows Mel as 4 units and Zack as 1 unit.

• Mel = 4 units → $28
• 1 unit (Zack) → $28 ÷ 4 = $7
• Total = $28 + $7 = $35

Mel and Zack saved $35 together.
Check: $7 × 4 = $28 = Mel. ✓