$1)$ If a company has $$10,000$ in revenue and $$7,500$ in expenses, what is its profit margin percentage?

$2)$ If you borrow $$5,000$ at $6\%$ annual interest for $3$ years, how much total interest will you pay by the end of the loan term?

$3)$ A bond pays $4\%$ annual interest on an investment of $$2,000.$ How much interest will you earn in $2$ years?

$4)$ A bond pays $4\%$ annual interest on an investment of $$2,000.$ How much interest will you earn in $2$ years?

all please, I have a calculations issue