querry about double fertilisation.: please clear my doubt about this double fertilisation….
Considering double fertilization in angiosperms, how many sperm are involved in the formation of a mature 2-seeded peanut pod?

According to my knowledge..double fertiliztion involves 2 male gamete (for every seed)..as follows..

one male gamete fuse female gamete to form zygote..which later forms embryo of seed
another male gamete fuse with diploid secondary nucleus to form Primary endosperm nucleus which forms endosperm in seed so now calculate yourself 🙂

… has quite correctly answered your question in double fertilization. Hence, two fruits are result of 2 double fertilization involving 4-sperms and 2- megagametophyte (Egg).

For more detailed information kindly go through the link provded http://en.wikipedia.org/wiki/Double_fertilization