Olaf has 250 files on an external hard drive of those files 12% are photos.(a)write a percent proportion to find the number of files that are phots.(b) how many phots does olaf have saved on his external hard drive?

A) Olaf has 250 files, which represent 100%. 12% of that are photos which number is unknown (x).
250 files - 100%
x photos - 12%
So, the proportion should look like:
250 files : 100% = x : 12%

B) After crossing the products:
x = 250 files * 12% : 100%
x = 30 photos