How many meiotic divisions are required for the formation of 100 functional pollen grains and 100 functional megaspores respectively ?

One pollen mother cell undergoes meiosis and forms four pollen grains . So number of meiosis required for formation of 100 pollen grains are 25 . one megaspore mother cell undergoes meiosis and forms four megaspores , among four megaspores three will gets degenerates and remaining one megaspore develops as functional megaspore . So to produce one functional megaspore one meiosis is required . 100 functional megaspores formation requires 100 meiosis .