Final answer:
The minimum number of investors needed to vote for a change in top management is 6. Investors 1 and 2 cannot be certain of getting their way in how the company is run.
Step-by-step explanation:
The minimum number of investors it would take to vote to change the company's top management is calculated by finding the total number of shares owned by all the investors and determining how many shares are needed to have a majority vote. In this case, the investors 1 and 2 own 20,000 and 18,000 shares respectively, which adds up to a total of 38,000 shares. To have a majority vote, more than half of the total shares should be owned by the investors voting for the change. Therefore, at least 50,001 shares are needed for a majority. Therefore, a minimum of 6 investors (1+2+3) would need to vote together for a change in top management.
However, investors 1 and 2 alone cannot be certain of always getting their way in how the company will be run. Even if they vote together, they would still need the support of other investors to reach a majority vote. With their combined 38,000 shares, they fall short of the 50,001 shares needed for a majority vote.