Answer:
2.4 hours Electrician works.
Explanation:
Let us assume that the number of hours Electrician works be x.
As given
An Electrician charges $30 for a service call plus $75 per hour of service.
If Electrician charged $210.
Than the equation becomes
30 + 75x = 210
75x = 210 - 30
75x = 180

x =2.4 hours
Therefore 2.4 hours Electrician works.