Lin Lin's family has some rice. Dad said: "30% of it has been eaten." Mom said: "If you buy another 90 kg, it will be the same as before." How many kg of rice did Lin Lin's family have?
林林家有一些大米，爸爸说："已经吃了30%，"妈妈说："如果再买进90千克，就和原来一样多．"林林家原来有多少千克大米？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">90 / (3/10)</gadget>
<output>300</output>

<result>300</result>