If k pencils cost c cents what is the cost in cents of p pencils

This is about circle theorems. someone asap : (

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?

Joey is asked to name a quadrilateral that is also a rhombus and has 2 pairs of parallel sides.should be his answer