Answer:
Ella
Step-by-step explanation:
Process of elimination will help here
5 girls, 1 is farthest left and 5 is farthest right
"Mary is not sitting on the farthest right side; "
"Dorothy is not sitting the farthest to the left."
"Sylvia is not sitting the farthest to the left nor the farthest to the right."
Mary could be in seats 1 2 3 4.
Dorothy could be in seats 2 3 4 5.
Sylvia could be in seats 2 3 4. And not next to Dorothy
Kathy could be anywhere not next to Sylvia
Ella is sitting anywhere on the right of Dorothy
I suggest assigning each girl a number 1 to 5 and then go through the list and see can this arrangement work
Kathy 1
Dorothy 2
Mary 3
Sylvia 4
Ella 5