need these questions answered please

Mr. Lothbrok has $10,000 to invest in two types of mutual funds, Coleman High-yield Fund, and Coleman Equity Fund. The High-yield fund gives an annual yield of 6%, while the Equity fund earns 10%. Mr. Lothbrok would like to invest at least $5000 in the High-yield fund and at least $2000 in the Equity fund. How much money should he invest in each to maximize his annual yield, and what is the maximum yield?

A DC license plate consists of 2 letters followed by 5 digits. How many such plates are possible?

You have a collection of 42 rubber ducks. Of these, 24 have yellow bodies, 15 have orange bills, and 6 have both. How many do not have either? Draw a Venn diagram.

How many 3-people committees consisting of 1 boys and 2 girls can be chosen from a group of four boys and four girls?

In how many ways can 4 English, 1 history, and 3 math books be set on a shelf, if they are grouped by subject?