The conversion from Gray Code to binary is simple.
Step 1
Write the number down and copy the left most digit under itself. (1 1 0 1 1 Gray Code = 1 Binary)
Step 2
Add the highlighted binary digit to the Grey code immediately up and to the right of it. So 1 plus 1 is 0 dropping the carry. Write the result next to the binary digit just added. Drop all of the carried digits. (1 1 0 1 1 Gray Code = 1 0 Binary)
Step 3
Repeat Step 2 until the number is completed.
1 1 0 1 1 Gray Code
1 0 0 Binary
1 1 0 1 1 Gray Code
1 0 0 1 Binary
1 1 0 1 1 Gray Code
1 0 0 1 0 Binary