Hello! The first step is to subtract 1500 from 1200 and you get 300. then you must see what 300 percent of 1500 is. So, simply divide 1500 from 300 and you get 0.2. Then when you make a percent, you multiply it by 100 which gives you 20%. That would be your final answer!
I hope this helped,
I am, yours most sincerely,
SuperHelperThingy