题目

    This Monday，the nation will start to celebrate Presidents’ Day，just seven days before George Washington’s birthday．Everyone agrees that day is a holiday，but is it just to celebrate George Washington’s Birthday? What about Abraham Lincoln? Some government offices call it Presidents’ Day．Others say the holiday is officially Washington’s Birthday．Confused yet?     George Washington was elected the country’s first President on April 30，1789．Soon after，Americans began publicly celebrating his birthday．Presidential historians say the actual date of有一容器，装满水时质量是O.4kg，装满密度为0.8×103kg/m3的煤油时质量是O.34kg，求容器的容积．如果用该容器装满密度是1.2×103kg/m3的盐水，总质量是多少？