Abill from a plumber was $306 the plumber charged $150 for parts and $52 per hour for labor. how long did ths plumber work at his job?

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!