Question 975221: There are seven children to be lined up in a straight line for a photograph
A. How many different ways possible?
b. How many different ways are possible if Sally must be in the middle?
c.How many different ways are possible if Ahmed is on the far left?
d. How many different ways are possible if Hannah and Brian must be together?
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! A. 7!=5040.
B. 6!=720. The other 6 may be chosen to fill the other spots.
C.Same thing. The first is fixed,but the other six are not.
D. Two are already chosen. There are 5! or 120 ways to choose the others. However, the two may appear in any of six places. I was mistaken earlier, for this is an order problem, so there are two ways each of them may be ordered, 12 altogether. That is multiplied by 120 to get 1440.
12
23
34
45
56
67
|
|
|
