Question 328371
let the number of P500 sacks he mixes be x
the P520 he mixes will be 100-x
..
mixture P515 100 bags
500x+520(100-x)=515*100
500x+52000-520x=51500
-20x=51500-52000
-20x=-500
x=-500/-20
x=25 -------- the p500 type
balance 75 will be P520 type sacks