could someone please help me with these? i cannot seem to figure them out

Find the present value of $400 due in the future under each of these cond tions: 4. 15% nominal rate, semianinual compounding, discounted back 6 years. Do not round intermediate cakculations. Round your answer to the nearest cent. b. IS*s nomiruil rate, querterly campounding, discounted back 6 years. Do not round intermediate calculations. Round your answer to the nearest cent. 5 C. 15\%w nominal rate, monthly campounding, discourted back 1 year. Do not round intermediate calculations. Round your answer to the nearest cent. 8