A student got 34 pencils for school. If she sharpen 16 of the pencils before school what is her ratio of unsharpened pencils to sharpened pencils

34 total pencils ... 16 were sharpened ... that means (34 - 16) = 18 pencils that were not sharpened.

so the ratio of unsharpened pencils to sharpened pencils is:

18:16 which reduces to 9:8 or 9/8 or 9 to 8 <==

34-16 = 18

so 18 are unsharpened

ratio is 18/16 reduced to 9/8