Mom took Xiaoyun to buy fruit. If she bought all the apples with the money she brought, she could buy 10 kilograms; if she bought all the pears, she could buy 15 kilograms. They bought 4 kilograms of apples and used the rest of the money to buy pears. How much more can they buy? Kilo pears?
妈妈带小云去买水果，带的钱如果全部买苹果，可以买10千克；如果全部买梨，可以买15千克，她们买了4千克苹果，用剩下的钱买梨，还能买多少千克梨？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 4</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(3/5) / (1/15)</gadget>
<output>9</output>

<result>9</result>