Answer: Your result (without simplifying) is actually 2/36, so you would shade two boxes out of the 36 shown.
NOTE: For problem #19, you have 6 boxes for shading, so each box represents 3 increments (3x6=18 boxes). For your result of 5/18, you should only shade the first box and 2/3 of the next box (the other four boxes should be unshaded).
Hope this helps!
Explanation: