Use the units method: the ratio tells us apples = 3 units and bananas = 5 units.<br><br>
[[model:questions/solutions/q7225.png]]<br><br>
&bull; 3 units → 12 apples, so 1 unit → 12 ÷ 3 = 4<br>
&bull; Bananas = 5 units → 5 × 4 = 20<br><br>
There are 20 bananas.<br>
Check: Apples : Bananas = 12 : 20 = 3 : 5. ✓