Question

Ian has 120 folders to file. So far, he has filed 36 of the folders. What percent of the folders does he have left to file?

Answer 1

120-36 = 84 <==== what he has left

84/120×100% = percentage of what he has left
70% = percentage aka answer.

Answer 2

The fraction of the amount of folders Ian did not file out of 120 is 84/120.  In order to convert this into a percent, divide both the numerator and the denominator by 1.2.  You will get 70/100.  This new fraction as a percent is 70%.  So, he has 70% of folders left to file. 

Hope the explanation helped!