Question 941457
 interest on  $12,000  @ 6 %  =  6 % of 12,000
 = {{{(6/100)*12000}}}
     ={{{6*120}}}
      = 720
 Interest on $3000  @ 3 %  = 3% of 3000
 ={{{(3/100)*3000}}}
    ={{{3*30}}}
    =90
total interest  = 720+90
    = 810
Result :$810