Bob is 1 unit (1050 cards). Brett has twice as many, so 2 units. Together they are 3 units.<br><br>[[model:questions/solutions/q3186.png]]<br><br>• Brett = 2 units → 2 × 1050 = 2100<br>• Together = 1050 + 2100 = 3150<br><br>Together the two boys have 3150 cards.<br>Check: 1050 + 2100 = 3150. ✓