Question 282968
allegation mixture 
    


          0%            80%


               50%

    80-50=30  and  50-0=50

ratio=30:50=====3:5


          3:5::x:10


          X=6 gallons
 second method

   let the added water be x at 0%

   x*0%+10*80%=50%(x+10)

        800=50x+500
    
         300=50x

         x=6 gallons