小敏在商店买了12支铅笔和5本练习本,其中铅笔每支x元,练习本每本y元,共花了4.9元.
两个实习生每人加工一个零件,加工为一等品的概率分别为23和34,两个零件是否加工为一等品相互独立,则这两个零件中恰好有一个一等品的概率为( )
It was commanded that the coal mine survivors ____ to the nearest hospital for treatment.