The little monkey mother bought a basket of bananas. The greedy little monkeys ate 30% of it at once, leaving 28 kilograms. How many kilograms did the little monkeys eat in total?
小猴妈妈买回了一筐香蕉，贪吃的小猴们一下子吃了30%，还剩下28千克，小猴们共吃了多少千克？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">28 / (7/10)</gadget>
<output>40</output>

<gadget id="calculator">40 * (3/10)</gadget>
<output>12</output>

<result>12</result>