Pls help me with this :)

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

The cost of turkey is directly proportional to its weight. if a 12-pount turkey costs $27, how much does a 16-pound turkey cost? a. $33.75 b. $36.00 c. $31.00 d. $32.50

Jonathan puts $400 in a bank account. each year the account earns 6% simple interest. how much interest will be earned in 5 years?