Xiaohong's family bought a bag of rice and ate it (5/8), leaving 15 kilograms. How many kilograms of rice did they buy? (Use equations to solve) What is the equivalent relationship of this question?
小红家买来一袋大米，吃了(5/8)，还剩15千克，买来大米多少千克？(用方程解)这道题的等量关系是？
<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">15 / (3/8)</gadget>
<output>40</output>

<result>40</result>