The results of a survey are shown. 40 students said that they walk to school. if 8% walk, 17% used a car and 75% used a bus, how many students were surveyed? how many students rode in a car? how many students rode the bus? write the percent of the number of students that walked, rode in a car, and rode in a bus as fractions in its simplest form

First, change all of your percentages to decimal points. Now we have 0.08, 0.17, and 0.75. 
Now, take 40 and divide it by 0.08. You get 500, so 500 students were surveyed. 8% of 500 is 40. 
Now take 500 and multiply it by 0.17 and you get 85. 85 students drive. 
Take 500 and multiply it by 0.75 and you get 375, so 375 students take the bus.
You can write your fractions using the number that walked, drove, or took the bus over the amount surveyed.