You can
put this solution on YOUR website!First calculate how much the cost actually decreased. $1500-$1200=$300
Now you want to figure out $300 is what percent of $1500 (your original cost) so you divide $300 by $1500 and get 0.2
Multiply 0.2 by 100 to turn it into a percent, and you find out that your computer's cost decreased 20%.