$450
Explanation:
The total income that Sam made last year is $23,400.
Since he worked 30 hours per week and worked all 52 weeks of the year, it means that the total number of hours that he worked for the year would be
52×30 = 1560 hours.
To determine how much Sam made per hour, we would divide the total amount made for the year by the number of hours worked. It becomes
Hourly rate = 23400/1560 = $15
Since Sam earns $15 per hour and he works 30 hours in a week, it means that his weekly rate would be
15×30 = $450