for clarification
is it right to assume that the majority shareholders (3 founders) will own 85% of the 100000 shares and the investors ( those who buy shares) will own the remaining 15%?
if not, how many shares are there actually (total shares allotted to majority shareholders and investors) and how many shares (percentage) will the majority shareholders hold and how many shares (percentage) are allotted for investors
Correct, although the investors will have significantly more votes per share than the founders. Once the IPO is over we will work out how many votes the investors need to give them a total of at least 45% of the voting power.