On the windowsill

On the windowsill, 6 different flowers in flower pots are to be arranged next to each other. Four are flowering (one of them is a primrose), the rest are decorative with leaves (one of them is a fern). Determine:
a) how many different arrangements can be created on the windowsill from the flowers;
b) in how many arrangements will the primrose stand right to the right of the fern;
c) in how many arrangements will the flowering flowers stand next to each other;
d) in how many arrangements will the fern not stand at the edge.

Final Answer:

a =  720
b =  120
c =  144
d =  480

Step-by-step explanation:

$a=6!=720$

$$\begin{gathered} 1pair+4 \\ b=(1+4)!=120 \end{gathered}$$

$c=3!\cdot 4!=144$

$$\begin{gathered} x=2\cdot 5!=240 \\ d=a-x=720-240=480 \end{gathered}$$

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