she worked 2.72 hours
Step-by-step explanation
Step 1
Let x represents the total hours she worked
then
an electrician charges $40 to come to your house,so
Fixed charge=40
and
she also charges $55 for each hour that she works,so
variable charge=55*number of hours
variable charge=55*x
variable charge=55x
Hence, the total cost is
Step 2
now, solve for x, when total cost = 190
Let
total cost=190
replace
Hence, she worked 2.72 hours.
I hope this helps you