Answer: He worked 40 hours that week.
Step-by-step explanation:
Given : The owner of an automotive shop devotes 90% of his workweek to supervising, sales and accounting tasks. In one week.
Let x = Number of hours he work in a week.
then, Hours for supervising, sales and accounting tasks = 90% of x
As per given ,
[tex]90\%\ of \ x= 36\\\\\Rightarrow\ 0.90x=36\\\\\Rightarrow\ x=\dfrac{36}{0.9}=\dfrac{360}{9}\\\\\Rightarrow\ x=40[/tex]
Hence, he worked 40 hours that week.