Answer:
He should work
hours in overtime.
Step-by-step explanation:
Let x represents the number of hours of regular time and y represents the number of hours of overtime,
Since, earnings are $24 per hour for regular time and $36 per hour for overtime,
Thus, total earning = (24x + 36y) dollars,
Here, x = 40 hours and total earning = $ 1200,
By substituting the values,
1200 = 24(40) + 36y
1200 = 960 + 36y
240 = 36y
⇒ 
Hence, he should work
hours in overtime.