A bottle full of oil weighs 950 grams. After half of the oil is poured out, the bottle weighs 550 grams. How much oil is in the bottle?
一只瓶子装满油后重950克，倒走一半油后，连瓶重550克，瓶子里原有多少油？
<gadget id="calculator">950 - 550</gadget>
<output>400</output>

<gadget id="calculator">400 * 2</gadget>
<output>800</output>

<result>800</result>