Question 262874
Let x potteries be sold at the original price of 10.50 and 
    y potteries be sold at the reduced price of 10.50-3 = 7.5
Total number of potteries x+y = 85  ...(1)
Total amount 10.50x+7.50y = 712.50  ...(2)
(1)*7.50 =>  7.50x+7.50y = 85*7.50= 637.50  ...(3)
(2)-(3)=>    3x = 75
             x = 25
(1)=> 25+y = 85
      y = 85-25 = 60