Answer:
$765
Explanation:
The computer sells for 15% less meaning that it sells for 85% of the original price. In math the word of means to multiply so we need to multiply $900 by 85% and to do that we'll need to convert 85% into a decimal which we can do by dividing my 100 and that gives us 0.85. 900 times 0.85=765. So the new price is $765
I hope this helps and please don't hesitate to ask if there is anything still unclear!