How many required for a Masternode?
the amount will be 10 million when masternodes are implemented
10 million is the most optimal. The less coins you need for masternode, the less sense from masternode. With the increase of masternodes rewards will drop.
More masternodes also means more decentralization, which should always be the goal for any network to have healthy security.
Now gives POS 108% a year . What is the meaning nod ?Кaждый дyмaeт : нoды пoднимyт цeнy , и я coлью этoт xлaм .Everyone thinks: nodes will raise the price, and I will pour this stuff .
how you come to 108%

? 9% every 35 days x10 90% every 350 days and 15 days rest per year

so its a bit over 90% per year.
But You have not considered : mined coins also make POS

70 days, then 140 days . Not?
you are right. you stake every 35 days with 9% more coins so its more than i said