27题?27题?
27题?设分钟为x.则:(6+x/60)360/12-x360/60=110180+0.5x-6x=1105.5x=70x=12又8/11x360/60-(6+x/60)360/12=1106x-(180+0.5x)=1105.5x=290x=52又8/11外出时间52又8/11-12又8/11=40分钟