2 bananas can be exchanged for 6 apples, 4 apples can be exchanged for 8 pears, and 5 bananas can be exchanged for how many pears.
2只香蕉能换6个苹果，4个苹果能换8个梨，5个香蕉能换多少个梨．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>