What is the answer for the three questions

The driver can drive around the track 54 times for $12. Thus for one dollar, he can drive around the track 54/12 times, or 4.5 times. If for each dollar he drives around 4.5 times, for 8 dollars, he can drive around 8*4.5 or 36 times.

If there are 207 students in 9 classes, in 1 class, there are 207/9 students, or 23 students per class. Since there are 23 students per class and there are  classes, there are a total of 23*6 or 138 students in total.

Liam practices 24 times in 4 days. Thus he practices 24/4 or 6 times per day. His brother practices 12 times in 3 days. Thus he practices 12/3 or 4 times a day. Thus their rates are not equivalent.