Take first the pay rate of the construction worker with the given details
pay rate = earnings/hours worked
where
earnings= $504
hours worked = 36 hours
pay rate = $14/hr
The problem stated that the true hourly wage is $4 more than the pay rate, thus
true hourly wage = payrate+$4
true hourly wage = $14+$4
true hourly wage = $18
The true hourly wage that will appear on his pay stub is $18.