I need help how to work it out to get these provided answers.

20. We buy a 180 -day bank bill with face value of $2 million at 8.65% p.a. (a) How much do we pay for it? (b) We hold the bill for 26 days and then sell it at a yield of 7.90% p.a. At what price did we sell and what is the holding period yield p.a? (Show all your workings and round off your result to two decimals) Ans: (a) P=$1,918,174.51 or $1,918,170.83 (if strictly keeping 5 decimals during workings) (b) Selling price =$1,935,486.37 or $1,935,490.11 HPY p. a=12.67%