Answer:
15
Step-by-step explanation:
The conditions for triangle side lengths are:
A + B > C
A + C > B
B + C > A
The reverse is true too, of course:
A < B + C
B < A + C
C < A + B
Note that it's just 'greater than', not 'greater than or equal to' ( ≥ )
With those in mind, if 15 and 1 are A and B:
15 + 1 > C
15 + C > 1
1 + C > 15
And those can be simplified to these:
C < 16
C > -14 ( can be ignored because of the next one)
C > 14
And finally:
14 < C < 16
The largest whole number that fits those requirements is 15.