Completing the frequency table, and using the percentage concept, it is found that 11% of students under age 15 travel to school by car.
[tex]P = \frac{a}{b} \times 100\%[/tex]
In this problem:
Hence:
[tex]P = \frac{18}{165} \times 100\% = 11\%[/tex]
Then, 11% of students under age 15 travel to school by car.
You can learn more about the percentage concept at https://brainly.com/question/10491646