Answer:
The student that makes a wage of $21 per hour is Tarek.
Step by step explanation:
To determine which student makes a wage of $21 per hour, we need to divide the total earned by the number of ours, to see what is the rate per hour of each one:
Amy:

Tarek:

For Kal and Paula, we need to cross multiply (proportional relationships) to get a rate for 60 minutes:
Kal:

Paula:

Therefore, the student that makes a wage of $21 per hour is Tarek.