The Coen family consists of a father, a mother, two children and a dog. A photographer is about to take the family's picture. How many different arrangements (of standing in a row) does the photographer have, if it is known that the father insists of standing by his dog?  Select the correct option.
A) 12
B) 24
C) 30
D) 48
E) 120
We need to find the number of arrangements of Father, Mother, Child-1, Child-2, and a Dog, so that F and M are always together.   Consider F and D to be one unit, then we would have total of four units: {FD}, {C1}, {C2}, {M}. The number of arrangements of these four units is 4!, but F and D within their unit can be arranged in 2 ways: {FD} or {DF}, so total number of arrangements is 4!*2=48.   Answer: 48.
<result>D</result>
The Coen family consists of a father, a mother, two children and a dog. A photographer is about to take the family's picture. How many different arrangements (of standing in a row) does the photographer have, if it is known that the father insists of standing by his dog?