It would be biased because one would assume that students can get to school by means other than those that put them 8n the parking lor. (Parking lot = car drivers who would be the only students sampled.). Others may ride to school by either parent or school bus who could drop them off somewhere else or possibly walk to school. The freshmen/sophomores would be excluded generally as they would be too young to drive altogether
If Teresa drove 936 miles in 13 hours, this would mean she would have driven 72 miles every hour. 72 times 9 equals 648. After 9 hours, she would have driven 648 miles.
3x4x1/2= 6inches Multiply the base by the height and after multiply by one half