5. . 1
---- - -----
6. . 2
5. . 3
----- - -----
6. . 6
5-3
-------
6
2
-----
6
= 1/3
B
The statement is contradictory, because it is said that every member of the family gives a gift to every other member of the family. And from 10 members, there are just 2 exchanging. Anyway, maybe they are only 2 members exchanging the gifts at that point in time.
So, each member will exchange 9 gifts (that is 10 members total minus herself), and 2 members are exchanging gifts at that point, so 18 gifts are being exchanged.
<span>560 = 14a+16b
560-14a=16b
b=(560-14a)/16
b=-7/8a+35
Answer is B</span>