Let us assume that a person works for 8 hours a day.
Let us assume that the person works for 5 days a week.
Wage earned per hour = $15
So, wage earned in 8 hours = 15*8 = $120
Now, wage earned in 1 day = 120
So, wage earned in 5 days = 120*5 =$600
As the person works for 5 days in 1 week
So, in 50 weeks, he will work = 50*5 = 250 days
So, total number of hours he must have worked = 250*8 =2000 hours
Now, per hour wage = $15
wage in 2000 hours = 15*2000 = $30000
Hence, the estimated wage a person earns in 50 weeks = $30000