the way i did it was, assume that 10% of 300 is 30...then take one percent (which in this case is "3") off of 30, for each percent it is lower then 10%, which in this case "7" would mean that you divide 300 by "21" which gives you:14.2857142...... it goes on with alot more numbers.
300
42.8571
300 divided by 1000 = 0.3. = 30%
300
14.2857
percent of 21 over 300 = 7%% rate:= 21/300 * 100%= 0.07 * 100%= 7%
42.8571
0.0667
21
60 divided by 300 multiplied by 100 = 20 Therefore 60 is 20% of 300.
3.8571
15