Justin Case has purchased a $250 000 home by putting 20% down and taking out a 25 year mortgage with semi monthly payments of $600 to finance he rest. The payments will be made at the end of each period. What was the quoted interest rate for the mortgage ( with semi- annual compounding?)

My question here..

When you say RATE= ( 24 *25, -600, 250 000* (1-20%) * 24

What exactly is this formula???

Are you saying 24 times 25 minus 600 times 80 percent of 250 000??

The formula

APR = ( Rate, Nper, -PMT, PV) * 25

Is the rate and NPR being multipled??? I need more information regarding this. Can someone clarify that for me and directly to a reference???

Thanks

Fouad B