how to do cash flow diagrams for a,b and ?

*154. How much money must be invested in an account that pays 6% per year in- terest to be worth $20,000 at the end of 8 years if (forgetting leap years and making "convenient" assumptions): a. Interest is compounded annually? b. Interest is compounded semi-annually? c. Interest is compounded quarterly? d. Interest is compounded monthly? e. Interest is compounded weekly? f. Interest is compounded daily? g. Interest is compounded hourly? h. Interest is compounded minutely? i. Interest is compounded secondly