Answer: The required number of guests served by Jess is 13.
Step-by-step explanation: Given that there are 111 guest attending a party there are 15 servers each server has the same number of guest to serve.
If Jess will serve any extra guest, then we are to find he number of guests served by Jess.
By division algorithm, we can write

So, 14 servers will serve 7 guests each and Jess will serve 7 guests along with extra 6 guests.
Therefore, the total number of guests served by Jess is given by

Thus, the required number of guests served by Jess is 13.