No. of meiotic divisions to produce specific no. of seeds
Assuming that you have studied megasporogenesis and microsporogenesis. To produce a seed, you require the production of pollen(n) and egg(n) and their fusion.

Let's start with pollen grain(n):


  4 pollen grains are produced after 1 meiotic division in the pollen sacs.


$$4~\text{pollen grains} = 1~\text{meiotic division}$$


  To produce 1 pollen grain.


$$ 1~\text{pollen grain} = 1/4~\text{meiotic division} $$


  For production of $x$ pollen grains.


$$ x~\text{pollen grains}=x/4~ \text{meiotic divisions}\quad(1) $$

Now coming to egg(n):


  Only 1 egg is produced after 1 meiotic division in the megasporangium.


$$ 1~\text{egg}= 1~\text{meiotic division}$$


  For production of $x$ no. of eggs.


$$ x~\text{eggs}=x~\text{meiotic divisions}\quad(2)  $$

For production of $x$ no of seeds(2n):


  $x$ pollen grains and eggs are required. No. of meiotic divisions to produce $x$ pollen grains and eggs.


$$x~\text{seeds}=x + x/4~\text{meiotic divisions} \quad\text{From}~(1)~\text{and}~(2) $$