Answer: There are 142 people at morning service and 124 people at evening service.
Explanation:
Since we have given that
Total attendance for Sunday's services = 266
Let the number of people at morning service be 'x'.
Let the number of people at evening service be 'y'.
So, our equation becomes

According to question, If there were 18 more people at the
morning service than people at the evening service.
Then, it becomes,

So, we put the above equation in eq(1), we get

and x = 18+124=142
Hence, there are 142 people at morning service and 124 people at evening service.