C. 8 Girls
3+2=5
20/5=4
4x2=8
The best estimate for the length of a car is about 13-15 feet wide.
After 500 trials, she should expect 0.16 * 500, or 80 red marbles. 0.16 is the frequency of red (8/50). If you extend this expected frequency to 500 trials, it will be 80.