A list of the world's 10 largest companies, in terms of value, contains 3 from the United

Question:

A list of the world's 10 largest companies, in terms of value, contains 3 from the United States, 4 from China, and 1 each from Australia, Brazil, and the United Kingdom. A potential investor randomly selects 3 of the companies to research further.
(a) Find the probability of X, the number of United States companies selected.
(b) Determine the mean and variance of X. Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...