The Pen Corporation issued a new series of bonds on Jan. 1 1990. The bonds were sold at par (1000), had a 12% coupon and matured in 30 years on December 31, 2019. Coupon payments are made semi-annual (on June 30 and December 30).

What was the price of the bonds on Jan 1995 (5 years later) assuming that interest rates had fallen to 10%?

The answer according to book is N=50, I=5, Pmt=60, FV=1000 and PV=1182.56.

Why does n=50? I understand everything else.