On January 1, 2013 and your broker calls you with a District of Columbia Revenue Bond

On January 1, 2013 and your broker calls you with a District of Columbia Revenue Bond with a 
6.875 % coupon issued on 1/1/2013, maturing in 20 years on 12/31/32 and callable on 12/31/22. The 
face value is $1,000 and the bond is selling for $1,250. Interest is paid at the end of each calendar 
year.

I am trying to find the Yield to Maturity of 20 and 10 years