In a survey of music preferences 81 out of 450 students said that they preferred country music what percent of the students preferred country music

To write 81/450 as a percent have to remember that 1 equal 100% and that what you need to do is just to multiply the number by 100 and add at the end symbol %.

81/450 * 100 = 0.18 * 100 = 18%

81/450 as a percent equals 18%