Answer: 15
Step-by-step explanation:
The combination of n things taken r at a time :-
[tex]^nC_r=\dfrac{n!}{r!(n-r)!}[/tex]
Given : A total of 6 family members will appear in a portrait.
If 4 of the family members may sit in the front row , then the number of combinations of family members may sit in the front row is given by :-
[tex]^6C_4=\dfrac{6!}{4!(6-4)!}\\\\=\dfrac{6!}{4!2!}=15[/tex]
Therefore , the number of combinations of family members may sit in the front row =15
