Let the total number of students in the row be denoted as N.
Robert is 10th from the left and 6th from the right, so the total number of students is:
N = 10 + 6 - 1 = 15
Stephen is sitting 3rd to the left of Robert, so Stephen is at position:
10 - 3 = 7
Now, to find Stephen’s position from the rightmost end, we calculate:
15 - 7 + 1 = 9