We can make an equation from this.
Our intial value is 150 for parts, and he works for 52 dollars an hour.
We can define h for hours and c for total cost.
Therefore, we have:
c = 150 + 52h.
We can set this equal to 306 dollars, as that's the given total cost:
306 = 150 + 52h
Subtract 150 from both sides:
52h = 156
Divide both sides by 2:
h = 3
He worked 3 hours.
hope this helped!