Rank the duration of the following pairs of bonds and write down your analysis about why?

a) bond a is an 8% coupon bond, with a 20-year time to maturity selling at par value. bond b is an 8% coupon bond, with a 2-year maturity time selling below par value.
b) bond a is a 20-year regular bond with a coupon rate of 8%. in the same market, bond b is a 20-year callable bond also with a coupon rate of 8%.