Find the yield to maturity of the following securities:

a. a secuirty paying $1,000 in one year, for which you pay $926 today.
b. A secuirty paying $80 one year from now and $1,080 two years from now for which you pay $1,050 today
c: a secuirty paying $50 every six months for the next five years (beginning six months from now) plus the return of the face value of $1,000 at theend of the five years, for which you pay $1,000 today.