If the 7 nested IFs ever present a problem, this formula can be
extended beyond 7 columns,

=IF(ISNA(MATCH("X",F7:J7,0)),"",COLUMNS(F7:J7)+1-MATCH("X",F7:J7,0)) in
K7

It chooses the result based on the first X encountered in the range
under test, reading from left to right.

HTH