Your table is correct and your equations are correct.
It must be your algebra.
We have: .
Add  and : .
Substitute into : .
A motorboat traveling with the current can go 30 miles in 2 hrs. Against the current , it takes 3 hrs. to go the same distance. Find the rate of the motorboat in calm water and the rate of the current!
My set up:
Let x = speed of motorboat in still water
Let y = speed of current
See attachment for table I created.
From the table, I created the following system of equations but got the wrong answers.
2x + 2y = 30
3x - 3y = 30
What did I do wrong?